When Pascuala’s 20-year-old son, Mateo, was shot and killed while walking down the street near their home, she did what Mexican authorities urge all victims of violent crime to do: she went to the local branch of her state prosecutor’s office and filed a formal criminal complaint. Pascuala hoped that the authorities would identify and prosecute the members of the criminal group that she believed was behind her son’s murder, and which continued to harass members of her community —especially young people.
For months, Pascula told Human Rights Watch, prosecutors refused to give her information about the case—a right all victims’ family members have under Mexican law. At one point, she recalls, a prosecutor told her to stop pursuing the investigation, or else she might “end up joining her son.” Eventually, after nearly a year, Pascuala said, she was able to get the case transferred to a different branch of the prosecutor’s office, in the capital of her state. She learned that, until that point, almost nothing had been done to investigate her son’s murder.
When the new prosecutor moved forward with the investigation, Pascuala received death threats. At one point, she was violently attacked by a group of people who told her if she didn’t retract her complaint, they would “leave you like we left your son.” She told Human Rights Watch she asked the authorities for protection, another right all victims have under Mexican law. She was given a phone number to call, for the police, although, she recalls, the prosecutor said he doubted they would be much help.
Prosecutors eventually arrested the person they believed to be the leader of the criminal group. When Human Rights Watch interviewed Pascuala, nearly four years had passed since Mateo’s murder. At time of writing, the trial had been postponed 14 times. Both Pascuala and the two witnesses in the case, whose testimony her lawyer said is crucial to obtaining a conviction, continued to receive death threats. With the help of a local human rights organization, Pascuala eventually obtained protection measures from the government. However, she told Human Rights Watch she feared that, if the witnesses are killed, or they decide not to testify out of fear, the case would likely to fall apart, and her community would continue to live in fear.
“People tell me, ‘Just leave it. You’re being threatened. God will do justice,’” Pascuala told Human Rights Watch. “I tell them, ‘There is a god, yes. But there are also authorities here on earth. Why don’t they do anything?’”
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Pascuala’s experience is far from unique. When Mexican President Claudia Sheinbaum took office in October 2024, she inherited a country ravaged by nearly two decades of violence, largely driven by conflicts between and within powerful criminal groups battling for control of the drug trade and other illicit businesses and widespread abuses committed by security forces with near-total impunity. Mexico’s homicide rate, at almost 25 per 100,000 in 2023, is one of the highest in the world. The real homicide rate may be even higher. Since 2007, more than 94,000 people have been reported missing and have not been found —alive or dead. Many Mexican cities regularly top global lists of the most dangerous places in the world. Three quarters of Mexican adults living in urban areas say that crime and insecurity are their number one concern.
Efforts over the past two decades to attempt to reduce criminal violence have largely focused on militarizing law enforcement, undermining due process guarantees for those accused of crimes, and politicizing the way judges are appointed. These strategies have led to serious human rights abuses and have not been effective at improving public safety or curbing the power of criminal groups. They have failed to address a core problem: the ineffectiveness of Mexico’s criminal justice system.
For victims of violence and their families, seeking justice and accountability through the criminal justice system can be costly, time-consuming, dangerous, and ultimately ineffective. Many victims and their family members face stigmatization and neglect by authorities. Those accused of crimes often suffer abuse, corruption, and a lack of due process. Unsurprisingly, nearly half of Mexicans report having little or very little confidence in the country’s justice authorities.
Ineffective investigations by criminal justice authorities are one of the main drivers of this problem. State prosecutors’ offices are responsible for both investigating and prosecuting most homicides in Mexico. Their results have been extremely poor. From 2010 through 2022, state prosecutors’ offices opened around 300,000 intentional homicide investigations but formally identified a suspect in only around 51,000 cases. That works out to an abysmally low clearance rate of 17 percent. Equally problematic is the fact that, while around half of homicide prosecutions lead to a conviction, many of these cases are based on evidence that has been altered, fabricated, or obtained through threats or torture.
Focusing on homicides, this report examines in detail why prosecutors’ offices in Mexico so rarely conduct thorough, impartial, rights-respecting investigations. It identifies ways to improve access to justice, so that people like Pascuala can obtain accountability, Mexicans can be safer and recover their trust in the justice system, and Mexico can comply with its obligations under international human rights law to ensure adequate investigations of violations of the right to life.
Over a two-year period, we interviewed around 150 investigators, prosecutors, defense attorneys, victims’ advocates, human rights organizations, family members of victims, academics, and other experts in 11 states. We observed court hearings, reviewed case files, examined data from public sources and filed hundreds of information requests to state and federal authorities.
We found a wide range of systemic problems that undermine investigations and affect the rights of both victims’ relatives and those accused of crimes. These included:
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A lack of qualified investigators, prosecutors, and forensic technicians in state prosecutors’ offices to address Mexico’s high number of homicides and, often, a lack of basic materials and resources needed to effectively investigate crimes and conduct forensic studies.
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Excessively formal and bureaucratic systems for coordinating investigations and sharing information between members of the investigative team, which can lead to serious delays in taking basic investigative steps and following up on cases.
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A lack of adequate protection for witnesses and victims’ family members, who are often terrified of facing retaliation from perpetrators if they cooperate with investigations.
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Perverse incentives and antiquated investigative practices that encourage prosecutors to build cases on evidence and testimony that is weak or has been altered, fabricated, or obtained through threats or torture.
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Weak oversight mechanisms that fail to effectively investigate allegations of corruption and abuse and fail to sanction or remove the officials responsible, which, in turn, discourage victims from reporting these problems.
The Mexican government’s main strategy to attempt to rein in criminal violence over the past two decades has been to deploy the military domestically to fight drug cartels and carry out other law enforcement tasks. It is an approach that, by any objective measure, has failed. In December 2006, when then-president Felipe Calderón declared “war” on organized crime and launched the first military operation targeting drug cartels, Mexico’s homicide rate was one of the lowest in Latin America. By 2010, it had nearly tripled.
Calderón’s successors have continued the strategy of militarization. In 2019, under former president Andrés Manuel López Obrador, the Federal Police was disbanded and replaced with the National Guard, a military force. In 2024, a constitutional reform was approved giving the Ministry of Defense permanent control over federal law enforcement. When President Sheinbaum took office, on October 1, 2024, there were around 230,000 soldiers deployed domestically. The military has been implicated in serious human rights abuses, including torture, extrajudicial killings, and enforced disappearances. The homicide rate has remained stubbornly high. And the criminal justice system remains as ineffective as ever.
Efforts and proposals aimed at improving the outcomes of the criminal justice system have, in many cases, focused on weakening due process guarantees and undermining judicial independence, with similarly poor results. Since 2008, Congress has expanded the list of crimes requiring automatic pre-trial detention three times, contributing to an increase in the number of people incarcerated, but no improvement in criminal justice authorities’ ability to obtain convictions for violent crimes. In 2020, the Attorney General even introduced a proposal, which was ultimately abandoned, that would have allowed prosecutors to use evidence that had been obtained through torture, alleging that previous reforms aimed at protecting the rights of the accused had turned the justice system into “a revolving door” and “multiplied the number of criminals.” In 2024, following repeated claims by then-president Andrés Manuel López Obrador that the ineffectiveness of the criminal justice system was the fault of “judges who favor criminals,” Congress approved a constitutional amendment that will require all state and federal judges to be removed from office and replaced by popular vote in 2025 and 2027. Candidates for judicial elections will be chosen by the government, Congress, and the Supreme Court. These changes are likely to increase political pressure on judges to issue rulings favorable to the government but will most likely do little to address the problem of poor investigations.
To address Mexico’s ongoing crisis of criminal violence, authorities should urgently take steps to improve the ability of prosecutors’ offices to effectively investigate violent crimes and dismantle criminal organizations. Authorities should ensure there are professional career tracks in state prosecutors’ offices with clear and objective rules for hiring, promotion, and removal that reward investigators and prosecutors based on their skill and integrity and remove and hold accountable those who commit abuses. They should invest more in training and resources for investigators and forensic technicians and ensure that all prosecutors’ offices have the experts and equipment necessary to quickly identify victims and analyze evidence.
The federal government should create a standard protocol for intentional homicide investigations and establish minimum standards for the level of forensic and technical capacity that all states must have in order to ensure effective investigations.
State governments should take steps to ensure that victims’ family members are able to participate in investigations. That means ensuring all state victims’ commissions have sufficient staff and resources to support victims and improving coordination between prosecutors’ offices and victims’ commissions. It also means creating effective systems to protect victims and witnesses from retaliation. At the same time, government authorities should ensure that prosecutors do not use the unwillingness or inability of victims’ family members to help with an investigation as an excuse to abandon it.
State and federal authorities should also take steps to improve oversight of state prosecutors’ offices, such as granting full autonomy and sufficient resources to internal affairs units, Inspector General’s offices, and state anti-corruption prosecutors’ offices to ensure these entities can effectively investigate and sanction accusations of wrongdoing. They should also create external control boards and citizens participation councils with the authority to oversee the work of these units.
Mexico has obligations under international human rights law to take steps to protect the right to life by conducting thorough, impartial, and rights-respecting homicide investigations aimed at identifying the truth about what happened to the victim and ensuring that homicide victims and their families are able to access remedy through the justice system. Authorities should also take much more effective steps to dismantle criminal organizations that are responsible for homicides.
Abusive public security policies, like militarization and arbitrary arrests and convictions, have been proven ineffective in complying with these obligations. Mexico urgently needs professional and effective criminal justice institutions capable of effectively investigating and prosecuting homicides. The Sheinbaum administration should focus on ensuring criminal justice authorities have the tools they need to deliver justice.
CNGMD National Census of Municipal Governments (Censo Nacional de Gobiernos Municipales y Demarcaciones Territoriales de la Ciudad de México)
CNIJE National State Justice System Census (Censo Nacional de Impartición de Justicia Estatal)
CNSPE National State Public Security Census (Censo Nacional de Seguridad Pública Estatal)
CNPJE National State Prosecutorial Census (Censo Nacional de Procuración de Justicia Estatal)
CNPP National Code of Criminal Procedure (Código Nacional de Procedimientos Penales)
CPEUM Mexican Constitution (Constitución Política de los Estados Unidos Mexicanos)
ENCIG National Survey of Government Quality and Impact (Encuesta Nacional de Calidad e Impacto Gubernamental)
ENPOL National Survey of People Deprived of Liberty (Encuesta Nacional de Población Privada de la Libertad)
ENVIPE National Survey of Victimization and Perception of Public Security (Encuesta Nacional de Victimización y Percepción sobre Seguridad Pública)
INEGI National Institute of Statistics and Geography (Instituto Nacional de Estadística y Geografía)
LGSNSP General Law on the National Public Security System (Ley General del Sistema Nacional de Seguridad Pública)
SESNSP Executive Secretariat of the National Public Security System (Secretariado Ejecutivo del Sistema Nacional de Seguridad Pública)
UNODC United Nations Office on Drugs and Crime
Build Real Professional Career Services in Prosecutors’ Offices
State prosecutors’ offices should take steps to ensure they can hire and retain sufficiently qualified and experienced investigators, prosecutors, and forensic technicians, remove those who commit abuses, reward the most skilled and rights-respecting investigators, and create incentives for these highly skilled investigators to work on complex and high-risk cases like homicides. One way of doing so would be to ensure that all professional career services have clear rules for hiring, promotion, advancement, assignment to specific units, salaries, and removal of staff based on objective, merit-based standards. Mexican law has required all states to establish these kinds of rules since 2009, but many have not done so.
Invest in Staff, Training, Materials, and Equipment
Many of the shortcomings Human Rights Watch found in homicide investigations were, in part, the result of extremely high caseloads, insufficient training on investigative techniques, and lack of necessary materials and equipment for conducting investigations. State prosecutors’ offices should ensure that authorities charged with investigating complex crimes are able to invest sufficient time in each case and that they are given the necessary resources to do so. To assist them in doing that, the federal government could establish guidelines and standards regarding maximum caseloads, minimum staffing levels, and the most important types of resources and equipment that state authorities should be required to provide.
Strengthen and Expand Oversight and Control Mechanisms
Corruption and abuse are widespread in state prosecutors’ offices and usually go uninvestigated and unpunished, largely due to the ineffectiveness of oversight and internal control mechanisms like Inspector General’s offices and internal affairs units. These units need more autonomy, staff, and resources to be able to effectively investigate and sanction abuses. Their role could also be complemented with the creation of external accountability mechanisms, a model recommended by human rights organizations and the UN Office on Drugs and Crime. These mechanisms would enable citizens, civil society groups, and other independent experts to review allegations of misconduct and recommend sanctions or rules changes.
Strengthen Victims’ Commissions
The participation of victims’ family members is not only a right, established in Mexican and international law, it is also crucial to effectively investigating many homicide cases. In order to ensure victims and their families are able to effectively participate in investigations, state governments and legislatures should take steps to strengthen their states’ victims’ commissions, many of which are chronically understaffed and under-resourced. They should also take steps to improve coordination between prosecutors and victims’ commissions. Prosecutors should make victims’ commissions aware of all relevant cases and make it easy for victims’ families and their legal advisors to access case files, to receive and contribute information about investigations, and to propose new acts of investigation.
Improve Protection for Victims, Families, and Witnesses
One of the main challenges prosecutors face when conducting homicide investigations is the serious, well-founded fear that many witnesses and victims’ family members have of retaliation from perpetrators if they cooperate with investigations. Authorities are failing to comply with their obligations under Mexican and international law to effectively protect witnesses and victims. All states should take urgent steps to ensure that effective protection is available to victims and witnesses, including by implementing existing witness protection laws and developing systems and programs to effectively protect people from retaliation.
Improve Coordination in Homicide Investigations
Ineffective and overly bureaucratic coordination is a real barrier to the effective investigation of homicides. For an effective investigation, state and municipal police, investigative police, prosecutors, and forensic authorities should talk directly with each other and be able to share relevant information and discuss theories of the case. Instead, these groups often operate independently and are reluctant to collaborate or share information openly. State prosecutors could solve this problem by implementing strategies that encourage people working on the same investigation to work collaboratively.
Protect Independence of Judges
State authorities should attempt to implement the recent changes to the judicial system in a way that safeguards the independence of judges from political influence. In the past, many state judges have faced political pressure to issue convictions and have enjoyed few protections against retaliation for rulings unfavorable to state officials. While the changes to the judicial system do little to address this problem, state legislatures can attempt to implement them in a way that protects judicial independence by setting objective standards for nominations and clear rules for judicial discipline tribunals.
Develop Strategic Prosecution Plans
In order for prosecutors to strategically use their limited capacity to manage high caseloads and effectively dismantle the criminal organizations responsible for homicides, they need clear, transparent, and predictable standards they can use to determine which cases and acts of investigation should take priority. These standards should ideally be part of a strategic prosecution plan developed in an open and transparent process, involving prosecutors, police, justice officials, civil society groups, and other experts. This plan should be publicly available and include measurable objectives with identified metrics and establish a follow up mechanism to regularly review progress and adjust priorities.
This report is based on two years of research in 11 states with varying homicide rates and levels of impunity: Chiapas, Coahuila, Mexico City, Mexico State, Michoacán, Morelos, Nuevo León, Oaxaca, San Luís Potosí, Tamaulipas, and Zacatecas.
Human Rights Watch conducted interviews with approximately 100 justice operators, mostly between July 2023 and February 2024, including investigative police officers and prosecutors from homicide units, attorneys from state public defenders’ offices, private lawyers, lawyers from human rights organizations who represent victims of crime, and legal advisors and other staff from state victims’ commissions who provide legal representation and other services to victims of crime. These interviews focused primarily on intentional homicide investigations and, for the most part, did not address femicide or other crimes.
In some cases, interviews with the staff of state prosecutors’ offices and victims’ commissions were arranged with the permission or assistance of the state prosecutor or the head of the state victims’ commission and were conducted during working hours in a meeting room at the office of the state prosecutor or state victims’ commission in small groups or individually. In many other cases, Human Rights Watch contacted prosecutors, public defenders, judges, and others directly and privately, without speaking to state authorities, and conducted these interviews outside of working hours in a separate location, like a rented office space, or through a video call. A Human Rights Watch researcher also accompanied one prosecutor to court to observe the proceedings in the initial stages of a femicide prosecution.
Human Rights Watch conducted all interviews with justice operators on the condition of anonymity to enable interviewees to speak freely regarding the challenges and weaknesses they perceive in their states’ criminal justice systems. This means that, throughout this report, these interviews are cited using only the interviewee’s job title and the month in which the interview was conducted, without mentioning their name, state, or employer.
In addition, Human Rights Watch conducted around 50 interviews with other experts involved in the criminal justice system, mostly between January 2023 and January 2024. These included representatives of organizations that advocate for criminal justice reform, representatives of human rights organizations that provide legal representation to both the victims of crime and those accused of crimes, academics who study the criminal justice system in Mexico, representatives of international cooperation agencies that fund criminal justice reform work, and experts from the consulting firms that implement criminal justice reform projects. Most of these interviews were conducted in person in Mexico City or Monterrey, or through video calls.
Human Rights Watch also interviewed representatives of two civil society collectives that search for missing people and interviewed five relatives of victims of homicide or disappearance.
All interviews were conducted in Spanish, except one, which was conducted with the assistance of a Spanish-Tsotsil translator. All translations from Spanish to English are by Human Rights Watch.
Human Rights Watch also obtained, reviewed, and analyzed a wide range of official data from the national statistics agency (The National Institute of Statistics and Geography, INEGI) These included:
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Data on the number of murders, suicides, and deaths by unidentified causes registered in the INEGI’s database of vital statistics, which collects data from official death certificates filled out by medical examiners in each state.
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Data on the staff, resources, and training of state and municipal police forces from the INEGI’s national censuses of municipal governments (CNGMD) and state public security systems (CNSPE), which are based on a questionnaire sent to state and municipal authorities every two years. The most recent census available at time of writing was conducted in 2023, asking authorities for information on 2022.
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Data on the staff, infrastructure, and activities of state prosecutors’ offices and state forensic authorities from the national prosecutorial census (CNPJE), based on a questionnaire sent to state prosecutors’ offices every year. The most recent data available at time of writing was from the 2023 census, which asked authorities for information on 2022.
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Data on criminal cases opened and verdicts issued, from the INEGI’s national state justice system census (CNIJE), which is based on a questionnaire sent to state court systems every year. The most recent data available at time of writing was from the 2023 census, which asked authorities for information on 2022.
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Information on people who were imprisoned on homicide charges, either in pre-trial detention, or having been convicted of homicide, from the INEGI’s survey of people deprived of liberty (ENPOL). The survey was most recently conducted in 2020 and 2021. INEGI workers visited 54 prisons around Mexico and conducted extensive interviews with more than 67,500 incarcerated people, including nearly 10,000 who had been convicted of homicide and around 3,000 who were in pre-trial detention on homicide charges.
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Information on the experiences of victims of crime from the INEGI’s annual victimization and perception of public security survey (ENVIPE). The survey was most recently conducted in 2024, asking respondents for information on 2023. INEGI workers visited more than 102,000 homes nationwide and used probabilistic models to extrapolate estimated results.
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Information on the experiences of corruption among people who reported crimes to their state prosecutor’s office from the INEGI’s survey of government quality and impact (ENCIG), which surveys adults in cities with a population of more than 100,000 and asks respondents about their experiences accessing government services. The survey was most recently conducted in 2023, asking respondents for information on 2022. INEGI workers visited 42,000 homes nationwide and used probabilistic models to extrapolate estimated results.
In many cases, the data state authorities provided to INEGI, particularly in the prosecutorial and justice system censuses, was incomplete. Some state authorities did not provide all the data requested by INEGI, did not provide data with the level of specificity requested, or provided data that appeared to be incorrect.
To fill in gaps and obtain additional data on information not covered by the INEGI censuses, Human Rights Watch filed around 300 access to information requests to state and federal authorities throughout 2023 and 2024. These included requests for more complete information on the number of homicide prosecutors and investigators employed in each state, the level of training that prosecutors, investigators, and forensic technicians received, the number of cases referred to state victims’ commissions, the number of homicide cases opened and concluded in state court systems, the number of victims and witnesses who received protection measures, and the number of pending arrest warrants for homicide in each state. All of these requests were made through the National Transparency Platform (PNT) run by the independent transparency agency, the National Institute for Access to Information and Personal Data Protection (INAI). The tracking numbers for transparency requests from which data was used in this report are listed in Appendix I. All original requests and responses are publicly available on the PNT and can be found by searching using the tracking numbers.
Human Rights Watch also reviewed information on homicide investigations, court cases opened, and sentences that had been obtained through access to information requests by the Mexican research and advocacy organizations Impunidad Cero and México Evalúa, which both produce regular reports on the functioning of the state and federal justice systems.
In many cases, the data from these three sources (Human Rights Watch’s access to information requests, other organizations’ access to information requests, and the INEGI’s censuses) varied to such an extreme as to cast serious doubt on the reliability of any of the three numbers. For example, the number of homicide cases that ended in a verdict in Baja California in 2021 was either 51 (according to the INEGI census), 254 (according to information obtained by Impunidad Cero), or 208 (according to information obtained by Human Rights Watch).
For each type of data or statistic mentioned in this report, Human Rights Watch attempted to use the source that seemed the most reliable or complete. In some cases, data from certain states was excluded because it was missing or appeared to be inaccurate. Data sources are always cited in the footnotes.
This report focuses on the crime of intentional homicide (homicidio doloso in most state criminal codes). All 32 Mexican states also separately penalize other types of killings, including femicide (feminicidio), which is usually defined as the killing of a woman for reasons related to her gender, and unintentional or accidental homicide (homicidio culposo). Many state prosecutors’ offices have separate units that investigate and prosecute each of these three types of crimes.
Throughout this report, when discussing criminal investigations, prosecutions, and verdicts, the term “intentional homicide” is used to refer only to the crime “intentional homicide” as defined by each state’s criminal code. It does not include investigations opened, prosecutions initiated, or verdicts issued for the crimes of femicide or unintentional homicide unless explicitly stated in the text.
In the initial section of this report, when discussing homicide rates and trends in Mexico, the general term “homicide” (with no qualifier) is used to refer to all deaths which a medical examiner determined were likely caused intentionally by another person, regardless of whether prosecutors later decided to investigate and prosecute those killings as a homicide, a femicide, or some other crime. This is because Mexico’s national statistics agency (INEGI) calculates homicide rates using information from death certificates filed by medical examiners, who determine only the cause of death and whether a killing was intentional, but do not make legal decisions about how these killings should be investigated or prosecuted. This means that homicide rates referenced in this report include all killings, regardless of whether they were later investigated as homicides, femicides, or some other crime.
Medical examiners in Mexico classify the cause and intentionality of deaths using the World Health Organization (WHO)’s International Statistical Classification of Diseases and Related Health Problems (ICD). Homicides refer to codes X85 through Y09, “Intentional Injuries – Assault.” INEGI does not include deaths resulting from the aftereffects of assault, code Y871, when calculating homicide statistics.
Over the past decade and a half, Mexico has experienced an explosion of criminal violence, most notably characterized by the persistently high homicide rate—one of the highest in the world—and a growing number of disappearances. Three quarters of adults in urban areas say that crime and insecurity are the number one problem facing their country. As in many other parts of the Americas, authorities and independent analysts have attributed a large number of homicides to organized crime and to the steady flow of firearms into the country from the United States.
Mexican criminal justice authorities have been remarkably ineffective at responding to homicides. State prosecutors’ offices, which are responsible for investigating and prosecuting the vast majority of homicides, rarely manage to identify and prosecute those responsible. Between 2010 and 2022, just around 17 percent of investigations for the crime of intentional homicide opened by state prosecutors’ offices led to an arrest warrant or a prosecution. Unsurprisingly, most adults in urban areas surveyed by the statistics agency say they have little confidence in authorities’ ability to fairly and effectively investigate and prosecute crimes.
Homicide in Mexico
For nearly two decades, Mexico has suffered extremely high homicide rates. In 2007, the homicide rate was around 8 per 100,000, one of the lowest in the Americas, following a sustained 15-year decline in homicides in the country. That year, then-president Felipe Calderón declared “war” on organized crime and began deploying Mexico’s military domestically to fight drug cartels. By 2010, the homicide rate had jumped to more than 22 per 100,000. Since then it has remained stubbornly high. The homicide rate hit a peak of 29 per 100,000 in 2020 before gradually falling to around 24.9 per 100,000 in 2023. This places Mexico’s homicide rate well above the United Nations Office on Drugs and Crime’s (UNODC) estimated average in the Americas of 15 per 100,000 and its estimated global average of around 5.8 intentional homicides per 100,000. International rankings by organizations like UNODC and Brazil’s Igarapé Institute, place Mexico’s homicide rate among the 20 highest in world.
Limited Information on Homicides
Since effective homicide investigations are rare, very little is known about most homicides in Mexico beyond some basic details. The vast majority of homicide victims in 2023, around 88 percent, were male. Most, around 53 percent, were teenage boys and young men aged 15 to 39. According to Mexico’s national statistics agency, in 2023, homicide was the principal cause of death for boys and men aged 15 to 44.
The vast majority of homicides in Mexico, around 70 percent in 2023, are committed with firearms. Both US and Mexican officials believe most firearms used in crimes in Mexico were purchased in the United States. A 2020 report by the US Government Accountability Office (GAO) found that, from 2014 to 2018, around 70 percent of firearms recovered from crime scenes by Mexican authorities and submitted to the US Bureau of Alcohol, Tabacco, Firearms, and Explosives (ATF) for tracing had originated in the US, although Human Rights Watch does not have information about the criteria used to determine which firearms Mexican authorities submit for tracing. And a 2024 study by the advocacy group Stop US Arms to Mexico, using data obtained from ATF and the Mexican Ministry of Defense through freedom of information requests found that around two-thirds of weapons recovered by Mexican authorities and submitted to ATF for tracing between 2015 and 2022 had been sold in the United States.
The Role of Organized Crime
Independent security analysts estimate that between one-half and two-thirds of homicides in Mexico are committed by organized crime groups. The private security consultancy company Lantia Consultores, which uses open-source data to track crime, estimated that organized crime groups committed approximately 55 percent (18,000 out of 32,000) homicides in 2023.
The prosecutors and investigative police officers interviewed for this report gave similar estimates regarding the percentage of homicides in their states that were committed in relation to organized crime. Most said they consider factors like the type of weapon used in the homicide, the location of the homicide, the victim’s identity and criminal record, and the circumstances in which the victim’s body was recovered when determining whether a homicide was related to organized crime. As one investigative police officer explained:
We know which areas of the city have an organized crime presence. If we see a killing with a high-caliber weapon in one of those areas, we know it was probably related to organized crime.
Another investigative police officer from a different state, said:
Most homicides in our state are related either to organized crime or drugs. If, for example, witnesses say it was a drive-by shooting, or the perpetrator knocked on the door, shot a gun, and then fled in a getaway car, it was probably related to organized crime. Sometimes, we submit the gun for analysis, and we find that it had already been used in another crime. Or sometimes they leave the body in a certain way, like it’s placed in a cooler, or it’s wrapped up in a banner with a message on it. And often, once we identify the victim, we find they had previously been detained for selling drugs.
However, some prosecutors and investigative police officers also noted that the term “organized crime” is often used very broadly to describe very different types of criminal phenomena and that the majority of homicides in their states were related to low-level disagreements between members of local gangs, rather than territorial disputes between transnational criminal organizations. As one investigative police officer said:
Organized crime can mean a lot of things. Often, we find someone who has been beaten up and killed and we call it organized crime. Really, it was a group of three or four teenagers who sold drugs. We call that organized crime because it was a group and there were drugs involved.
In another state, a prosecutor said that:
The majority of the homicides in my city are usually young people, 18 to 40, fighting over drug money. Like, the victim owed 500 pesos (US$25) for drugs. He didn’t pay. So, someone drives by on a moped and shoots him. Or maybe he was selling drugs for one group and then he switched to another group. So many times, I go to the crime scene and I see it’s just a teenager.
Additionally, as described later in this report, prosecutors often assume that victims of homicides are themselves members of organized crime groups and frequently fail to investigate such crimes, downplaying their importance of ensuring accountability for these victims.
A Small Number of Violent Cities
While Mexico’s national homicide rate is high, the majority of homicides in the country are committed in just a few cities and states, which can mean that focusing only on national data can obscure the true scale of violence in certain regions.
According to mortality data from Mexico’s national statistics agency, more than half of homicides in 2023 occurred in only 50 of Mexico’s nearly 2,500 municipalities. Meanwhile, in around 1,750 municipalities, there were fewer than 5 homicides in 2023. The average homicide rate in these municipalities was around 7 per 100,000. In 916 Mexican municipalities, there were no homicides reported in 2023. The top ten most violent municipalities, representing around 8 percent of Mexico’s population, accounted for 23 percent of homicides in 2023. The average homicide rate in these 10 municipalities, as calculated by Human Rights Watch, was around 72 per 100,000 in 2023—nearly three times the national rate.
These municipalities are frequently ranked as having some of the highest homicide rates in the world. In 2023, the Igarapé Institute, a Brazilian think tank, found that four Mexican cities: Ciudad Obregón, Sonora; Tijuana, Baja California; Celaya, Guanajuato; and Ciudad Juárez, Chihuahua, ranked among the 20 cities with the highest homicide rates in the world.
Possible Homicide Undercount
Disappearances
There are a number of reasons to suspect that Mexico’s true homicide rate may be higher than the official number. The first is the rapidly growing number of unresolved disappearances reported in Mexico over the past decade. Since 2007, as homicide rates have climbed, the number of people reported missing and not found has also increased. And while homicide numbers have fallen slightly in recent years, the number of unresolved disappearances has continued to climb. More than 10,000 people reported missing in 2023 have not been found, the highest number on record. According to the official government missing person’s registry, as of February 2024, more than 94,000 people reported missing since 2007 have not been found. Around 79 percent of them are men.
In some states the increase in disappearances has been particularly stark. In Mexico City, for example, a significant fall in reported homicides since 2018 has been accompanied by a sharp increase in unresolved disappearances, which surpassed the number of reported homicides in 2023. Mexico City was one of seven states, along with Baja California Sur, Coahuila, Durango, Nayarit, Tabasco, and Tamaulipas, where the number of unresolved disappearances reported in 2023 was close to or surpassed the number of homicides reported that year.
There are a number of reasons to believe that many of the unresolved disappearances reported in recent years may represent homicides which have yet to be included in official statistics because victims’ remains have not been recovered. Between 2006 and 2023, authorities and activists uncovered nearly 5,700 clandestine graves across the country, many with dozens or hundreds of human remains, according to government data and reports by investigative journalists. Journalists have calculated that at least one clandestine grave has been uncovered in 23 percent of all municipalities. According to information journalists obtained from state forensic authorities, around 72,100 bodies or human remains processed by morgues between 2006 and 2023 were declared as unidentified and buried in municipal mass graves.
State morgues often struggle to identify skeletal remains and those that are decayed or no longer intact. Even when they do, these cases do not necessarily lead to homicide investigations, since it can be difficult to determine the cause of death from remains recovered from clandestine graves, a necessary step in determining whether a homicide has occurred.
A 2024 report by the International Crisis Group, based on interviews with members of organized crime groups, soldiers, and forensic authorities, found that criminal groups were increasingly taking steps to hide evidence of killings by disposing of victims’ remains in clandestine graves in order to avoid falling afoul of the government. The report said that:
According to various criminal leaders, the key to avoiding military operations to is to refrain from overt displays of violence. In practice, that appears to entail hiding corpses. As one criminal leader put it “Those that have to go… we need to make them disappear.” Criminal groups appear to prefer hiding victims in clandestine graves in hinterlands with little or no state presence.
Deaths with Unknown Intentionality
Another reason to suspect the official homicide rate may not reflect the full scale of homicides in Mexico is the high number of deaths which have been classified as deaths with unknown intentionality in some states in recent years.
When classifying deaths by external causes (also known as accidental or violent deaths), medical examiners in Mexico attempt to determine two things: the immediate cause of death (for example, stabbing, gunshot wound, poisoning, etc.) and the intentionality of the death (accident, homicide, suicide, or unknown). From 2018 through 2022, between 7 and 8 percent of accidental or violent deaths nationwide were classified as having an unknown intentionality. However, in some states, the proportion of deaths classified this way was much higher. In Mexico City, for example, the percentage of accidental or violent deaths with unknown intentionality ranged from 31 percent to 47 percent between 2018 and 2022. In Hidalgo, Jalisco, Puebla, and Mexico State, between 10 and 15 percent of deaths in this period were classified as having unidentified intentionality.
Journalists and public policy analysts have debated the cause of these high numbers of deaths with unknown intentionality. In a series of articles, published in 2023 and 2024, some speculated that medical examiners in these states were initially classifying many deaths as having an unknown intentionality pending further investigation and then failing to provide the Ministry of Health with updated death certificates when the cause of death was eventually determined, leading the final cause of death to be registered as “unknown” in official statistics.
However, in the 2024 report by the International Crisis Group, researchers said they had interviewed morgue workers and state officials who said that they had witnessed “murders being logged under other causes of death or going unrecorded, allegedly because of political pressure to reduce the recorded rate of lethal violence.” The report cited one morgue worker who reportedly told researchers that “[w]hen we received bodies of people who had clearly been gunned down or presented coups de grâce, those were often qualified as accidental deaths.”
In November 2024, when the national statistics agency published complete data on deaths in 2023, the proportion of deaths with unknown intentionality had fallen precipitously in many of these states (just 8 deaths were registered this way in Mexico City in 2023, down from 1,549 in 2022). The one notable exception was Baja California, where the proportion of deaths with unknown intentionality rose to 12 percent. Officials have not explained the sudden decrease in deaths with unknown intentionality, which may be due to a change in coding procedures or data inaccuracies.
Whatever the reason for the disproportionately high numbers of deaths with unknown intention registered in recent years, the result was that possible homicides among them were not counted in national homicide statistics.
Homicide Investigations
Mexico has a federal system, which means that each of the 32 states has its own state prosecutor’s office, its own state court system, and its own state penal code. Intentional homicide is generally considered to be a crime under the jurisdiction of state authorities and, except in certain exceptional circumstances, nearly all intentional homicides and femicides are investigated and prosecuted by state authorities in state court systems.
State prosecutors’ offices are responsible for both investigating and prosecuting all crimes under each state’s jurisdiction. In most states, at least on paper, the prosecutor’s office is an autonomous agency, separate from the rest of the government, and the state prosecutor is appointed by the state legislature rather than the governor.
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The Transition to the Adversarial System Between 2006 and 2016, all Mexican states transitioned their state justice systems from an inquisitorial model, in which most evidence is presented in writing, to an adversarial model, in which the prosecution and defense present competing arguments in court, before a judge. Under the new system, most evidence is presented orally, prosecutors are prohibited from using confessions made without a defense attorney present, and most court hearings are video recorded and open to the public. As part of the transition, Mexico adopted a National Code of Criminal Procedure (CNPP), in 2014, which establishes standard rules that apply in all states for the investigation and prosecution of crimes. Since many investigations and prosecutions were already underway when each state transitioned to the adversarial system, all states currently operate both an inquisitorial court system (commonly referred to in Mexico as the “traditional system”) and an adversarial court system. Crimes committed before each state transitioned to the adversarial system are investigated and prosecuted under the traditional system. Since investigations and prosecutions took significantly longer under the traditional system, many intentional homicide cases opened under the traditional system are still pending. Most state prosecutors’ offices have separate units for prosecuting homicide cases open under the traditional system. This report focuses primarily on investigations and prosecutions carried out under the adversarial system. All of the prosecutors interviewed for this report said they worked exclusively on cases under the adversarial system. Many said they had only begun working at their state prosecutors’ offices after the transition to the adversarial system and were unaware of how the traditional system operated. The statistics, quotes, and other information presented throughout this report focus primarily on the adversarial system. Data regarding cases opened under the traditional system have been excluded unless otherwise specified in the text. |
When an investigation is opened, it is usually assigned to an individual prosecutor, who is responsible for deciding how to proceed with the investigation and which investigative steps should be taken. All prosecutors’ offices have their own police forces, usually called investigative police or ministerial police, who are responsible for carrying out the specific acts of investigation requested by the prosecutor in charge of each case. Most state prosecutors’ offices also have a forensic medicine and expert services department, responsible for operating the state morgue, processing crime scenes, and analyzing evidence when requested to do so by prosecutors. This department is usually staffed by medical examiners, crime scene technicians, sketch artists, and specialists in a wide range of other fields related to criminal investigation, such as fingerprint analysis, ballistics analysis, DNA analysis, forensic dentistry, property appraisal, fire and explosives, topography, and forensic accounting.
While all state and many municipal public safety departments have police forces, these police officers (usually referred to as preventative police) usually do not participate in criminal investigations. Their role is generally limited to securing crime scenes and waiting until officials from the prosecutor’s office can arrive to begin investigating. State and municipal police can also detain anyone they catch in the act of committing a crime or immediately afterwards (in flagrante) in order to immediately present the person before prosecutors, who can decide whether or not to open a formal criminal investigation.
Steps in Mexican Criminal Procedure
As way of background, the following sections summarize some of the key steps in Mexican criminal procedure as they relate to the findings of this report. This section is not intended to serve as an exhaustive explanation of Mexican criminal procedure.
Initial Investigation
In all states, prosecutors are required to automatically open an investigation when they become aware of a suspected intentional homicide or femicide. Once an investigation is opened, prosecutors, investigative police officers (who work in prosecutors’ offices), and forensic technicians are legally required to make a record of all acts of investigation they conduct as well as all evidence they obtain. The National Code of Criminal Procedure allows them to do this by any means that ensures the information is recorded “completely, integrally, and exactly” and ensures that it can be shared with victims and defendants. Typically, officials record this information in writing. Each of these documents is then added to a case file (carpeta de investigación) as a record of the steps taken in the investigation. The investigation centers around the case file. Non-written evidence, such as audio or video recordings, is typically sent to an analyst, who reviews it and then writes a written report summarizing its contents to be included in the case file. Statements by witnesses and victims are recorded in writing, signed by the witness or victim, and included in the case file.
Most intentional homicide investigations begin with the crime scene inspection reports filed by the investigative police officers and forensic technicians who processed the initial crime scene. Once these reports have been filed, it is up to the prosecutor leading the case to decide what subsequent investigative steps to order, such as an autopsy of the victim’s body, forensic analysis of evidence recovered from the crime scene, or investigation to identify potential witnesses.
Investigative methods can vary. While Mexico has established standardized national protocols for the investigation of disappearances, torture, and crimes against journalists, no such standard protocol exists for the investigation of intentional homicides or femicides. And while 24 state prosecutors’ offices have independently established protocols for the investigation of crimes against women, only four have established a protocol for investigating intentional homicides.
Initiating Prosecution (Citation/Warrant/Arrest)
When prosecutors have identified a suspect and obtained evidence they believe demonstrates there is a likelihood that the suspect participated in committing a homicide (probable cause), they can initiate a criminal case by requesting that a control court judge issue a citation (which instructs the person under investigation to appear in court for the initial hearing) or an arrest warrant (if there is reason to believe the person under investigation would not respond to a citation). A prosecution can also be initiated if state or municipal police officers arrest someone in flagrante–in the act of committing a crime or immediately afterwards—or in “urgent cases,” in which prosecutors can argue they did not have time to obtain a warrant before conducting an arrest. In these cases, they must present the arrested person before a control court within 72 hours of arrest.
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Control Courts and Trial Courts There are two main kinds of courts in Mexico’s adversarial criminal justice system: control courts (juzgados de control de garantías) and trial courts (juzgados de enjuiciamiento). All cases begin in control courts and most of the steps of a prosecution take place in these courts. Many cases are resolved in control courts, through an abbreviated procedure (in which the defendant agrees to be found guilty in exchange for a reduced sentence) without proceeding to a full oral trial before a trial court. |
Initial Hearing (Vinculación a Proceso)
If a suspect voluntarily complies with a citation or if the investigative police arrest a suspect, all parties to the case (prosecutors, the victim, the victim’s legal advisor, the suspect, and suspect’s lawyer) will appear in control court at the initial hearing. Prosecutors will present preliminary criminal charges (called an imputación in Mexican law) based on the evidence they have obtained so far in the investigation. At this stage, they must only demonstrate there is a “probability that the defendant committed or participated in the commission” of a crime (sometimes referred to in English as probable cause). Prior to the hearing, prosecutors must give the defense a copy of the case file, including all evidence and written witness statements. The defense is permitted to challenge or question the evidence presented during the hearing or request an extension to obtain exculpatory evidence. If the control court judge finds there is probable cause, they issue a decree of vinculación a proceso, which allows prosecutors to continue their investigation. In intentional homicide and femicide cases, if the judge issues a vinculación a proceso, they are required to order pre-trial detention, although formal criminal charges have still not been presented. If the control court judge does not find sufficient evidence for a vinculación a proceso, the defendant is usually released.
Complementary Investigation
Following vinculación a proceso, the control court judge grants prosecutors up to six months of additional time for “complementary investigation” to attempt to obtain additional evidence. At the end of this period, prosecutors must decide whether to seek a suspension, dismissal, or present a formal criminal indictment (called an acusación in Mexican law). During this time, in an intentional homicide or femicide case, the person under investigation must remain in pre-trial detention, according to Mexican law. Prosecutors may interrogate them or encourage them to agree to accept a guilty sentence without going to trial in exchange for reduced jail time (known as an abbreviated procedure).
End of Complementary Investigation (Criminal Charges, Suspension, or Dismissal)
Once the time limit for the complementary investigation has expired, prosecutors, the defendant, and the victim return to the control court to tell the judge whether they have decided to present a formal criminal indictment or request that the case be dismissed, allowing the defendant to be released. Up until this stage, the prosecutors, the victim, and the defendant may agree to an abbreviated procedure (meaning the defendant agrees to be found guilty without going to trial). If they do not accept an abbreviated procedure, the prosecutors can ask the judge to issue a decree referring the case to trial court for an oral trial.
Abbreviated Procedure (Plea Bargain)
If the defendant agrees to be found guilty in an abbreviated procedure (usually because they agreed to do so during the complementary investigation period), the control court judge will ask prosecutors to present all the evidence against the defendant, including any additional evidence, witness statements, or confessions obtained during the complementary investigation period. Witnesses are not called to give their testimony orally; only written witness statements are used. If the control court judge determines that the evidence is sufficient to corroborate the charges, they may issue a guilty verdict.
Oral Trial
Before a case proceeds to oral trial, the control court judge will hear arguments from the prosecution, the defense, and the victim to determine which pieces of evidence can be used at the oral trial.
At the oral trial, in trial court, the prosecution and defense present their arguments. They can call witnesses, such as police officers, medical examiners, and forensic technicians, to testify to the information in their initial written statements. The trial is usually open to the public and is audio and video recorded. If the judge finds that there is evidence to demonstrate “beyond all reasonable doubt” that the accused is responsible, they can issue a guilty sentence.
Ineffective Homicide Investigations
Attempting to quantify the effectiveness of homicide investigations can be difficult. The two metrics most commonly used to measure the effectiveness of homicide investigations are the clearance rate, which is usually defined as the percentage of all homicides in which authorities have identified an alleged perpetrator and initiated the process of presenting criminal charges, and the conviction rate, which is usually defined as the percentage of homicides in which the alleged perpetrator has been tried and found guilty through a judicial process.
In Mexico, these rates are typically calculated by comparing the number of investigations opened each year for intentional homicide and femicide by prosecutors’ offices, the number of pending intentional homicide and femicide investigations at the close of each year, the number of court cases initiated each year for these crimes in state court systems, and the number of guilty and not-guilty verdicts issued for these crimes by judges.
The yearly intentional homicide clearance rate and the conviction rate can be useful metrics for gauging the effectiveness of the system overall, but they are also imperfect and problematic for a number of reasons.
First, these metrics do not measure the extent to which homicide prosecutions were based on effective, impartial, and rights-respecting investigations. As discussed later in this report, homicide investigations in Mexico can often involve abuses against those accused of homicide and are not always aimed at determining the truth about what happened to the victim. They sometimes use evidence that has been altered, fabricated, or obtained through threats or torture.
Second, while these metrics show the total number of cases, they do not provide information about the criteria that authorities are using to prioritize which cases to focus on.
Finally, there are also challenges in ensuring that data on clearance rates and conviction rates accurately represent the pipeline of the criminal justice system. Not all states in Mexico use the same system for recording and storing information on homicide investigations and prosecutions, meaning it can be difficult to obtain comparable data from each state to conduct an accurate comparison.
Clearance Rates
From 2010 through 2022, Mexican state prosecutors opened nearly 300,000 criminal investigations for suspected intentional homicide, representing around 79 percent of the known homicides during this period. During that same period, they initiated just over 51,000 prosecutions for intentional homicide in state court systems, meaning that the average clearance rate for intentional homicide cases was around 17 percent.
The most recent Global Study on Homicide published by UNODC in 2023 using data from 82 countries from 2021, found that Mexico’s homicide clearance rate is well below the global average but is very similar to the rates in other parts of the Americas. In Asia, there were 19 suspects for every 10 homicide victims in 2021. In Europe, there were 11 suspects per 10 homicide victims. In the Americas, there were just 4 suspects identified for every 10 homicide victims. Human Rights Watch calculated, using UNODC methodology and data, that in Mexico there were around 3.2 suspects identified for every 10 homicide victims in 2021.
Many of the intentional homicide investigations that go unsolved each year are either closed without ever presenting criminal charges or are “archived” (archivo temporal) due to a lack of evidence. In 2022, for example, state prosecutors’ offices opened around 28,700 intentional homicide investigations, initiated a prosecution in around 5,300 cases, and closed or archived around 10,000 others. Many other cases are simply left open, pending further investigation. At the close of 2022, for example, state prosecutors’ offices reported having around 63,000 pending investigations for intentional or unintentional homicide.
Rates of Verdicts and Convictions
While most intentional homicide investigations in Mexico do not lead to a prosecution, it appears that, when prosecutors do identify and arrest a suspect and initiate a prosecution, most of these cases lead to a verdict.
In 2022, state courts received around 5,300 requests from prosecutors to initiate a criminal case for intentional homicide (not including femicide). That year, state court systems reported that judges issued around 3,900 verdicts for intentional homicide, equivalent to around 74 percent of the intentional homicide prosecutions opened that year, which likely included some cases initiated in previous years. Just under half were guilty verdicts issued in an oral trial and another 28 percent were guilty verdicts issued through an abbreviated procedure.
That works out to a conviction rate (the percentage of investigations that lead to a conviction) of around 9 percent in 2022, and a rate of cases that led to a verdict (including both guilty and not-guilty verdicts) of around 14 percent. These rates vary widely from state to state. The two states with the highest rates of cases that led to a verdict or conviction, Baja California Sur and Yucatán, are also among the states with the lowest intentional homicide rates.
According to the most recent UNODC Global Study on Homicide, Mexico’s intentional homicide conviction rate is well below the global average and the average rate in the Americas. The study, which used data from 82 countries for 2021, found that, globally, an average of 4 people were convicted for intentional homicide for every 10 intentional homicide victims. In the Americas, that rate was around 2 people convicted for every 10 intentional homicide victims. In Mexico, UNODC found that around 0.5 people were convicted for intentional homicide for every 10 victims in 2021 and around 0.9 were convicted for every 10 victims in 2022.
Looking at data over a longer period of time shows similar results. In 2022, the Mexican criminal justice reform organization Impunidad Cero found that, from 2016 through 2021, there were just 7 guilty verdicts issued for every 100 intentional homicide investigations opened during that period.
This low rate of effectiveness does not just affect homicides. A recent analysis of the effectiveness of Mexico’s criminal justice institutions conducted by the think tank México Evalúa found that in 2023, just around 6.4 percent of all criminal cases were resolved.México Evalúa, which publishes annual reports on the justice system, looked not just at the number of guilty verdicts issued but at a broader range of ways that criminal cases can be resolved.Mexican law allows for many less serious types of crime to be resolved through mediation, dispute resolution agreements approved by prosecutors’ offices, or reparatory agreements made before a judge, in which the person accused of a crime agrees to make reparations to the victim, financially or otherwise, instead of being sentenced to jail time. The report also found that, taking into account both new intentional homicide investigations and pending cases opened in previous years, only around 3 percent of pending intentional homicide cases were resolved in 2023.
Femicide Investigations
In most states, clearance and conviction rates for femicide (the killing of a woman for reasons related to her gender) are significantly higher than those for intentional homicide, although, as some Mexican organizations have documented, there are also frequently failures and irregularities in femicide investigations. In 2022, around 4,000 women were killed (around 12 percent of all homicide victims that year) and state prosecutors’ offices opened around 950 investigations for femicide. That year, state courts received nearly 1,100 requests from prosecutors to initiate a femicide prosecution and issued around 540 guilty verdicts for femicide. These likely included some cases from the previous year, since at the close of 2021, state prosecutors’ offices reported having around 1,050 pending investigations open for femicide. Looking at the numbers only for 2022, the clearance rate for femicide cases is around 114 percent, the rate of cases which led to a verdict (guilty or not guilty) is around 67 percent, and the conviction rate is around 60 percent.
Previous analyses by Mexican organizations have found similar results. For example, in Impunidad Cero’s 2022 report on homicide and femicide investigations from 2016 through 2021, the organization found that, during that period, for every 100 femicide investigations opened, there were 43 guilty sentences issued. As with intentional homicides, Impunidad Cero found that conviction rates for femicide vary widely from state to state. In some states, like Oaxaca and Tlaxcala, the conviction rate was close to zero, while in others like Aguascalientes and Zacatecas, it was close to 90 percent.
Many of the prosecutors and investigative police officers interviewed for this report cited two reasons they believed that most femicide investigations were often more effective than intentional homicide investigations. First, they said, while most intentional homicides in Mexico are suspected to be related to organized crime, often making them more difficult to investigate, most femicide cases are related to intimate partner violence. Prosecutors said they usually begin these cases with a clear line of investigation, focused on the victim’s romantic partner or another member of their family. Second, in the states where prosecutors’ offices have a dedicated unit for investigating femicides or violent crimes against women, the prosecutors working in that unit said that they usually have lower caseloads than their colleagues in the homicide unit, allowing them to dedicate more time to each individual case.
An Alternative Indicator: Citizens’ Trust in the Justice System
Given the limitations of focusing only on clearance and sentencing rates, it can be useful to look at other ways of evaluating the effectiveness of Mexico’s criminal justice system, such as citizens’ confidence in the authorities.
Most people in Mexico say they have little confidence in the justice system. In the most recent survey on citizens’ perception of public services, conducted in 2023, which surveyed adults living in urban areas, only around 4 percent of respondents said they had “a lot of trust” in state prosecutors’ offices or in judges. Around 55 percent said they had “a little bit of mistrust” or “a lot of mistrust” in these institutions. The only institutions that ranked lower in terms of citizens’ trust were police, labor unions, and politicians. In the same survey, state prosecutors’ offices and state judicial systems were ranked among the institutions that respondents viewed as most corrupt. Nearly 75 percent said they believed corruption was “very frequent” or “frequent” in prosecutors’ offices and around 66 percent said the same in judicial systems. The only institutions they ranked as more corrupt than prosecutors’ offices were police forces and political parties.
Given this lack of confidence, it is unsurprising that, in the most recent survey on crime, also conducted by the national statistics agency, which asked respondents about their experiences with crime and the justice system in 2023, most respondents who had been victims of crime said they did not bother to report these incidents to authorities. The agency estimated that just around 7 percent of the crimes committed in 2023 were formally reported to prosecutors’ offices. Around 60 percent of people said they did not file a report because they believed doing so would have been “a waste of time,” because they did not trust the authorities to investigate, because they were afraid of being revictimized or extorted, or because of excessive bureaucracy at prosecutors’ offices. Among those who did file a formal criminal complaint, nearly half said they had been treated “badly” or “very badly” by officials at their local prosecutors’ office. A third said the process of reporting the crime took four hours or longer. And a quarter said that officials refused to open an investigation.
Nearly everyone Human Rights Watch interviewed for this report, including prosecutors, legal advisors, defense attorneys, judges, investigative police officers, forensic specialists, academics, and justice reform advocates, agreed that the central problems limiting authorities’ capacity to effectively investigate homicides are lack of staff, lack of resources, lack of training, and poor coordination between officials.
In many states, low salaries, lack of job stability, and challenging working conditions make it difficult for prosecutors’ offices to hire and retain sufficient numbers of qualified staff to investigate the high numbers of homicides committed every year. Police, prosecutors, forensic technicians, and investigators also frequently do not receive the training, equipment, and resources needed to effectively investigate homicides or to store and identify victims’ remains. Adding to the problem, the way that many prosecutors’ offices are structured can mean there is often poor coordination between prosecutors, investigative police officers, and forensic technicians working on the same case.
The following sections describe these shortcomings as they affect each of the main authorities involved in homicide investigations in Mexico.
State and Municipal Police
State and municipal police officers (officially called preventative police officers in many states to distinguish them from the investigative police officers who work at prosecutors’ offices) are typically the first authorities to respond when a homicide takes place, usually because officers on patrol are likely to be the closest to the scene of the crime.
In most cases, state and municipal police officers do not participate in criminal investigations. Their role is usually limited to acting as first responders at a crime scene. When they receive a report of a possible homicide, federal government guidelines say they should notify the prosecutor’s office, secure the crime scene until investigative police officers and crime scene technicians from the prosecutors’ office arrive and keep a record of anyone who enters or exits the crime scene.
They can also begin securing any evidence found at the crime scene, taking photographs to document the crime scene, and taking statements from witnesses while they wait for officials from the prosecutor’s office to arrive to collect it and formally initiate an investigation. They can also arrest anyone they encounter in the act of committing a crime, or immediately afterwards, in order to present the person to prosecutors.
When first responders fail to properly secure a crime scene, evidence can become contaminated, making it much more difficult for investigative police and prosecutors to determine the facts of the case later on.
In theory, all police officers should receive training on how to respond to and preserve crime scenes. Federal government guidelines, established in 2017, say that the initial training for state and municipal police officers should include at least 60 hours of training on the initial steps in a criminal investigation. All police officers are also legally required to hold a valid Unique Police Certificate (Certificado Único Policial, CUP), a certification which must be renewed every three years and requires 40 hours of training, including 8 hours of training on responding to crime scenes.Mexican law says that police officers who do not hold a valid CUP should be removed from service. The deadline for police forces to comply with this law and ensure 100 percent of their officers hold a valid CUP has been repeatedly postponed since the requirement was established in 2016. Most recently, in December 2023 authorities postponed the deadline to December 2025.
A significant number of state and municipal police officers do not hold a valid CUP or have not completed an approved training course. At the close of 2022, 23 percent of state police officers and 38 percent of municipal police officers did not hold a valid CUP, and 36 percent of state police officers and 29 percent of municipal police officers had never completed a training course. Levels of training vary significantly between states. In 12 states, for example, 100 percent of state police officers have completed a training course, while in five others, fewer than 15 percent of state police have completed one of these courses.
Some of the prosecutors and crime scene technicians interviewed for this report said that, while the level of training for police officers on how to preserve crime scenes has improved in recent years, as more police officers have completed these training courses, many officers still commit errors that can lead to evidence being lost or contaminated. In some cases, for example, prosecutors and forensic technicians explained that police officers often forget to include important details when filling out the initial crime scene report, like the position in which the body was found, or whether paramedics arrived at the scene to try to revive the victim. This can create problems later on, if the case makes it to trial, because officials often review these documents to prepare their testimony and can end up testifying to a version of events that does not match the details of the case.
One prosecutor from a unit that investigates homicides and femicides of women said:
In my state, prosecutors usually go to the initial crime scene inspection. I’ve been to crime scenes where, when I arrive, the municipal police are walking all over the place before the crime scene technicians arrive to take photos. I dealt with a case recently where a police officer left a big shoe print in a blood stain. I had to take a photo of the shoe print and then go and try to find all the police officers who had been there to compare it to their shoes. In another case we had recently, we were trying to find the victim’s phone and eventually we realized a police officer had stolen it.
Additionally, most state and municipal police in Mexico work under precarious conditions, with little job stability, low salaries, long hours, and few benefits. For example, nearly half of municipal police officers regularly work shifts that are 24 hours or longer. And a recent study by the federal government agency responsible for setting the minimum wage found that, in 18 of Mexico’s 32 states, the average police officer’s salary is below the minimum amount required to meet basic needs like food and housing. Police officers often need to use their own money to purchase some of the basic materials required to do their jobs, like parts of their uniforms, bullets, or gasoline. As a result, police sometimes do not have the materials they need to properly secure a crime scene, like caution tape.
Limited coordination between police forces and staff of prosecutors’ offices is also often a problem. Some of the prosecutors and crime scene technicians interviewed for this report said that local police officers can be reluctant to share information with them. In some cases, they said, even when police officers are fully trained on how to respond to crime scenes, they are more focused on carrying out the instructions of their commanding officers, who have asked them to report back with photos, videos, and other information, rather than quickly securing the scene. As one crime scene technician explained:
Often, when I get to a crime scene, the police haven’t put up any caution tape yet. They are looking around and taking photos because they say their commander asked for a report on the incident as soon as they arrived.
A homicide prosecutor in a different state mentioned a similar issue:
Often, the police don’t want to share information with us. They were the first ones to arrive at the crime scene. They might recognize people, or they might have seen a car fleeing the scene. But there’s a lot of jealousy between prosecutors and the police, so we never get that information.
Forensic Technicians, Medical Examiners, and other Specialists
Forensic technicians, medical examiners, crime scene technicians, and other specialists play two important roles in criminal investigations. These specialists are typically among the first authorities to arrive at a crime scene, following state and municipal police, and are responsible, together with investigative police officers, for examining the crime scene, and collecting or taking samples of any relevant evidence. Once all the relevant physical evidence has been collected and returned to the forensic laboratory, these technicians are responsible for conducting any necessary analysis, such as an autopsy of the victim, analysis of blood and hair samples, or fingerprint analysis. If a case makes it to trial, they will typically be called to testify in court regarding the findings of the forensic studies they conducted during the investigation. They are also responsible for conducting any studies necessary to identify victims’ remains —a crucial step in any homicide investigation.
Forensic and expert services divisions in many state justice systems are often significantly understaffed and underfunded. Many states struggle to hire and retain sufficient numbers of qualified forensic technicians and medical examiners in the wide range of specialties required to investigate complex crimes, often due to low pay and poor working conditions. In some forensic specialties, staff turnover can be high. In addition, few states provide sufficient training for forensic technicians, despite the wide range of specialties they are required to cover. And in many states, forensic technicians and medical examiners lack the basic materials and resources needed to carry out key parts of their jobs.
Insufficient Staff and High Caseloads
One of the most pressing challenges affecting forensic capacity in many states is a lack of qualified staff to quickly and effectively collect and analyze evidence and identify victims’ remains. In many states, that means forensic technicians and other specialists deal with extremely high caseloads.
There is no universally accepted international standard regarding the capacity or maximum recommended caseloads of forensic experts. In some countries, like the United States, national forensic authorities have established guidelines regarding the maximum number of cases a medical examiner should receive in a year. Mexican authorities have not established such guidelines. However, they have acknowledged that high workloads are a challenge for forensic technicians in many states. In 2022, the attorney general’s office conducted a diagnostic of forensic capacity at a state level, focused on capacity for human identification. The report found that:
[T]he information obtained demonstrates the lack of, and need for, trained personnel and specialized spaces that can not only meet the demand for experts, but also reduce the persistent and increasing backlog. Additionally, it should be noted that some technicians and laboratories are not exclusively dedicated to their specialty area.
[…] [Some] technicians, in addition to performing the substantive functions for which they were hired, carry out the functions of other specialty areas, as well as data entry and administrative functions. This circumstance is the result of a lack of specialized administrative and support personnel required for the correct and complete functioning of these institutions.
The forensic technicians interviewed for this report said that high workloads are a significant challenge limiting their ability to dedicate sufficient time to each case, even in states with the most well-funded forensic services departments. One forensic technician, who had been trained as a fingerprint analyst but said he was often assigned to work as a crime scene technician, described his workload:
There were just one or two of us on call for each zone in the state. We worked 24-hour shifts. Each team had one criminologist and one or two interns who were studying medicine or criminology at the local university. The investigative police were supposed to come to the crime scene and bring the evidence back to the prosecutor’s office after we had collected it and bagged it, but they usually never showed up, so the interns were in charge of keeping track of the evidence in the truck. Usually we had multiple events back-to-back, so we would rush to get everything done quickly and drive straight from one crime scene to another. You work a 24-hour shift and then, at the end, your vehicle is full of evidence from all these different crime scenes, and you need to go back to the office and start writing all the reports from the crime scene in your “time off.”
Some states face a significant backlog of forensic studies. In the most recent national prosecutorial census, conducted by the national statistics agency in 2023, nine states’ forensic authorities reported that the number of pending forensic studies at the end of 2022 was equivalent to 10 percent or more of the total number of forensic studies ordered that year. In Zacatecas, which has seen a massive increase in violent crime in recent years, the forensic backlog was 51 percent. In Baja California, which consistently ranks as one of the places with the world’s highest intentional homicide rate, the backlog was 44 percent.
High caseloads can also limit the amount of time that forensic technicians can spend preparing to testify in court regarding the results of their forensic analyses. Some forensic technicians and legal advisors from state victims’ commissions interviewed for this report said that it is common for forensic technicians to be ill-prepared when appearing in court.
Other interviewees cited additional reasons for their limited preparation for hearings including that they are often given little notice before hearings and not included in broader discussions about the status of the case, which can make it difficult to get quickly up to speed before testifying. This can lead to serious problems, including cases being overturned, as one legal advisor from a state victims’ commission explained:
One problem we’ve had many times is that the judge orders a re-trial because of problems in the testimony given by the medical examiner or the crime scene technician. A lot of times, it’s because the defense attorney argues that the technician wasn’t actually testifying, they were just reading verbatim from a report. Sometimes the defense attorney asks the forensic technician a follow up question and it becomes clear they don’t actually know what the case is even about, so they say something that’s incorrect, or that contradicts someone else’s testimony. And sometimes, it’s because they made an error in the initial report, like it says the victim died on July 6th, but it was actually July 7th, and then, because they’re just reading from the page, they repeat that error in court.
Poor Recruitment, Training, and Promotion Systems
Another challenge is the difficulty many states’ forensic authorities face in recruiting, training, and retaining qualified forensic and criminology technicians. By their very nature, positions in forensic medicine departments and expert services divisions require high levels of specialized training and education. However, in the states where Human Rights Watch conducted research, staff and directors from state forensic services divisions said that they are rarely able to recruit candidates who already have the experience or qualifications required to work in a morgue or forensic laboratory. Instead, they said, they usually aim to hire recent graduates with degrees in fields like medicine, criminology, psychology, or chemistry, and provide them with initial and on-the-job training.
Federal law requires that technicians complete a training course that has been approved by the Executive Secretariat of the National Public Security System (SESNSP), a federal body that sets minimum training standards. The SESNSP asks all state authorities to submit the curricula of their training courses for evaluation and approval. However, in response to an information request filed by Human Rights Watch, the SESNSP said that only eight states offered training programs for forensic technicians that met the minimum federal requirements. Some forensic technicians interviewed for this report said that, in their states, people working in forensic services are typically hired with no prior experience and are expected to learn on the job.
Some forensic technicians and criminologists said their departments often offer training opportunities, but that they are usually expected to take these courses in their free time, in addition to their normal work.
Compounding the problem of limited training is the difficulty that many state authorities face in retaining experienced criminologists, medical examiners, and forensic technicians. In the states where Human Rights Watch conducted research, forensic staff said high turnover, especially among criminologists, can make it difficult to retain institutional knowledge. Often, they said, the low salaries, long working hours, limited job stability, and unclear rules for professional advancement create incentives for more experienced technicians to leave after a few years to look for work in other states or in the private sector. As the director of a state forensic services department explained:
Salaries are a challenge. Everyone earns the same salary, regardless of how long they have worked in the department. So, it can be very hard for us to retain the most skilled criminologists. Once they have a little bit of experience, they leave to find a higher paying job.
In another state, two criminology technicians interviewed for this report expressed similar concerns:
If there were some kind of system for us to get promoted based on experience, I think more people would stay. But instead, a lot of the smartest people leave after a month or two. Once they see how hard this job is, going out into the field, the long hours, and they realize that, no matter your performance or your seniority, you earn the same salary, they decide to look for other opportunities.
High turnover of forensic staff can also make it hard to follow up on older cases and lead to problems if a case makes it to trial but the forensic technician who participated in the investigation is no longer working at the prosecutor’s office, some legal advisors said. As one explained:
Usually, when we get involved in a case, it has already been open for a year or two. If we find problems with the forensic studies, it can be really hard to correct them because the technicians who conducted the studies are long gone. I dealt with a very complicated case recently involving multiple victims over the course of a few years. The case only moved forward when one of the victims’ mothers, who is a lawyer, got involved. We found that many of the autopsy reports were missing information or had errors. To get the case to trial we had to go find the forensic technicians at their homes. It was a lot of work.
In another state, legal advisors said that prosecutors are often reluctant to prosecute cases after the forensic technicians who worked on them have resigned because they believe that it would be too difficult to contact them and that, without their testimony, it would be extremely difficult to obtain a guilty sentence. As one legal advisor said:
In our state, once the forensic technicians quit, it’s an excuse for the prosecutors to say “well, this case can’t go to trial.” Sometimes, even if we track down the technicians ourselves, the prosecutors still don’t let them testify because they don’t work for the prosecutor’s office anymore. In those cases, the prosecutors can try to get a plea bargain, but if the defendant refuses, then there isn’t really another option.
Insufficient Morgue Capacity
Compounding the problem of high caseloads and long delays in conducting forensic studies is the lack of adequate space in many cities to properly store evidence and human remains while they await analysis or identification. As the graph below shows, nine state morgue systems reported holding significantly more human remains than their official capacity at the close of 2022. In Veracruz for example, the state’s morgues can officially hold around 880 human remains in refrigerators and another 615 that do not require refrigeration (such as skeletal remains). However, at the close of 2022, state authorities reported nearly 4,600 human remains being held in the state’s morgues and forensic laboratories.
In some complex cases, prosecutors may need to order additional studies that cannot be performed at their local morgue, such as dental analysis or DNA testing to identify remains. In states that do not have these capacities, this can mean holding remains in storage and sending samples to federal authorities for analysis, legal advisors said. In states that do have the capacity to perform these types of studies, they are usually only practiced in one laboratory, typically located at the main forensic services office in the state capital. Victims’ remains must be held in storage for weeks or months at the local morgue while the studies are conducted elsewhere.
This can present additional challenges, since many local morgues have extremely limited storage capacity. In 2022, for example, 38 morgues in 11 states (around 20 percent of all morgues in the country) reported having no working refrigerators. Around 20 percent of morgues reported holding more human remains than their maximum capacity in 2022, including seven morgues that reported holding remains in storage despite having no storage capacity at all.
Legal advisors at the office of one state’s victims’ commission located in a smaller city, who cover a large rural region of their state, said that prosecutors in their city sometimes avoid ordering more complex forensic testing that could help identify remains or solve cases, due to lack of adequate space to store remains in their local morgue. As one legal advisor explained:
Storage at the morgue in our city is a big problem. It’s very hot here and the refrigerators don’t work very well. They can’t hold remains for more than a few days because they start to decompose. I’ve had cases where a victim’s remains are found after a few days, but they are already unrecognizable because of the heat. The prosecutor’s office will refuse to order a DNA test, because it would take two months to send the sample to the capital and get the results back and they can’t store a body for that long. So they pressure families to do a visual recognition and take the remains even though they are not sure it’s actually their family member.
Insufficient Resources for Collecting, Storing, and Analyzing Physical Evidence
Forensic technicians also said they are often not given sufficient materials and resources to effectively carry out forensic analysis. This problem can affect homicide investigations from the very beginning. Sometimes, as one technician, who has worked for her state’s forensic division for 12 years, explained, this can mean that technicians are forced to use their own money to buy basic materials needed to respond to crime scenes. She said:
The forensic technicians who work on homicides and femicides here in the state capital are all very experienced, which is good. But they don’t give us a lot of the basic materials we need to respond to a crime scene. We get gloves, printer paper, and plastic bags. Everything else, if you want to do your job correctly, you need to buy yourself. That means things like the plastic evidence markers that you put on the ground to take crime scene photos, measuring tape or electronic distance meters. And at the end of the financial year, there is no money left even for the things they are supposed to give us. We end up paying out of our own pockets for things like paper and gasoline to put in the car to drive to and from the crime scene.
A criminologist in a different state explained how equipment shortages in the state’s forensic laboratory can lead to delays in analyzing evidence:
The forensic laboratory in our state just isn’t big enough to handle the increased number of crimes in recent years and the amount of evidence that needs to be processed. For example, when evidence comes in from a crime scene, it needs to be dried in a drying cabinet before it can be analyzed. But, right now, we only have one drying cabinet. That means that the evidence is sitting there waiting, sometimes for weeks, before we can put it in the drying cabinet. And that means it can take even longer for technicians to actually get around to conducting the studies and issuing the forensic reports.
Some private attorneys and legal advisors from state victims’ commissions said that, in their experience, crime scene technicians, investigative police officers, and prosecutors sometimes try to limit the number of forensic studies they order in each case due to limited resources in their states’ forensic laboratories. One private lawyer, who has represented the families of intentional homicide and femicide victims, said:
In some cases where we are representing the victim’s family, we’ve found that the forensic technicians only conducted a basic autopsy, but didn’t do things like order blood tests to see if the victim had been drugged before she was killed. When we ask prosecutors to request basic blood tests, they reply to us and say “We don’t have enough reagent to conduct all the blood tests you’ve asked for. Please pick only the most important test and we’ll conduct that one.” If we want the other testing to get done, we need to either fight with the prosecutors or tell our client to pay out of their own pocket.
A legal advisor from a state victims’ commission in a different state said she had seen cases where investigative police officers and crime scene technicians simply did not collect evidence in the first place, knowing that there was no capacity to analyze it:
I recently represented the family of a young woman who was found murdered in a hotel room. When we looked through the case file, we discovered that crime scene technicians had never collected samples of the blood stains on the bed. That seemed like a major omission to me. I asked the prosecutor what happened with the samples—did they forget to include them in the version of the case file they sent to us? He told me they never took any samples. That there was no point, since there was no money to get them analyzed anyway.
Investigative Police
Investigative police officers (sometimes referred to as judicial police or ministerial police) play a central role in criminal investigations. Under the direction of prosecutors, they are responsible for carrying out most of the concrete investigative steps that take place outside of the prosecutors’ office. They participate in crime scene investigations, interview witnesses, search for and collect physical evidence, obtain footage from security cameras, coordinate with other government agencies to obtain records and other information related to cases, and execute arrest warrants.
Human Rights Watch found shortcomings in the organization and training of investigative police forces that limit investigative officers’ ability to effectively carry out these tasks in murder investigations. Despite their title, investigative police officers often carry out a wide range of responsibilities unrelated to investigating crimes. In many states, they are treated more like traditional police officers and receive limited training on investigative techniques. They are not always responsible for the same investigation from start to finish, but may instead be assigned to carry out investigative tasks related to multiple investigations. Additionally, in many states, there is no formal process to determine which officers are assigned to work in units investigating high-impact crimes like intentional homicide, and no additional training or pay for these officers. In fact, in some cases, the rules around training promotion appear to actively disincentivize investigative police officers from working on high-impact crimes.
A Wide Range of Responsibilities
State prosecutors’ offices employed around 23,800 investigative police officers in 2022—accounting for around 25 percent of all staff. Around 17,000 officers were assigned to units that investigate and prosecute crimes. Despite their title, the investigative police officers interviewed for this report said that they and many of their colleagues often spend much of their time on a wide range of non-investigative responsibilities, including serving as bodyguards, drivers for senior officials, or security guards at buildings operated by the prosecutor’s office. Others serve on state ‘SWAT’ teams or in ‘apprehension’ units, responsible for conducting arrests and executing arrest warrants.
Some prosecutors, crime scene technicians, and investigative police officers said that this wide range of responsibilities can sometimes limit the number of investigative police officers who are available to participate in investigations at any time or limit the amount of time that officers have to carry out key investigative steps and lead to delays. One former crime scene technician, for example, said that in his state, investigative police officers were often too busy to respond to crime scenes, even though that should be one of their primary responsibilities. As a result, he said, crime scene technicians were often left to collect evidence on their own, or with the assistance of local police officers:
According to the procedures in my state, the investigative police officers were responsible for arriving at the crime scene as quickly as possible in order to make sure the scene had been properly secured by the local police and make sure the record of everyone who entered and exited was included in the chain of custody documents. They were also supposed to take any evidence we collected from the crime scene and bring it back to the forensic laboratory so that we could go directly to the next event. But often, they didn’t show up. That could mean the chain of custody documents never get filled out properly. And it sometimes meant we had to bring the evidence with us from crime scene to crime scene, which made it easy for things to get mixed up in the van.
|
Investigative Police Officers Assigned to Homicide Units |
|
|
State |
Investigative Police Officers Assigned to Homicide Units |
|
Aguascalientes |
11 |
|
Baja California |
84 |
|
Baja California Sur |
10 |
|
Campeche |
No homicide unit. |
|
Coahuila |
No information available. |
|
Colima |
0 |
|
Chiapas |
No information available. |
|
Chihuahua |
68 |
|
Mexico City |
148 |
|
Durango |
No information available |
|
Guanajuato |
No information available. |
|
Guerrero |
5 |
|
Hidalgo |
18 |
|
Jalisco |
No information available. |
|
Mexico State* |
84 |
|
Michoacán |
58 |
|
Morelos |
No information available. |
|
Nayarit* |
10 |
|
Nuevo León |
No information available. |
|
Oaxaca |
24 |
|
Puebla |
279 |
|
Querétaro |
20 |
|
Quintana Roo |
No homicide unit. |
|
San Luis Potosí |
No information available. |
|
Sinaloa |
63 |
|
Sonora |
57 |
|
Tabasco* |
15 |
|
Tamaulipas |
No information available. |
|
Tlaxcala |
No information available. |
|
Veracruz |
No homicide unit. |
|
Yucatán |
0 |
|
Zacatecas |
0 |
|
Sources: Number of investigative police officers assigned to homicide units is from information requests to state prosecutors’ offices filed by Human Rights Watch. See Appendix I for a complete list of information request numbers. For states marked with asterisk (*), the number of investigative police officers assigned to homicide units is from INEGI, CNPJE 2023, Module I, Section I, Questions 4 and 23. |
|
Lack of Incentives to Focus on Investigation
The investigative police officers interviewed for this report said their departments’ rules around promotion and salaries sometimes discouraged the most skilled and experienced officers from working on homicides or other complex crimes. Some told Human Rights Watch that they viewed working in the homicide unit as an undesirable assignment, given to newer officers or assigned as punishment for poor performance. Most agreed that the most coveted positions are those working as a bodyguard, driver, or security guard since these roles are easier, often entail lower risks, and most importantly, they said, come with a salary increase. In the states where Human Rights Watch conducted research, officers explained that they are typically not eligible for merit or seniority-based raises or promotions, meaning that one of the only ways to obtain a salary increase is by seeking a transfer to a non-investigative role.
Some homicide prosecutors and legal advisors from state victims’ commissions said that this can lead to frequent turnover among the officers working on homicide cases, as more experienced officers are moved to other assignments and replaced, which can be detrimental to the investigation. As one prosecutor explained:
In my opinion, one of the biggest problems is the rotation of investigative police officers assigned to work on our cases. Interviewing witnesses is a skill that takes time to learn. And not everyone is good at it. You need to convince people to talk to us and make them feel comfortable telling the truth. It’s very difficult when they constantly are assigning us new investigative police.
Limited Investigative Training
While the federal government has established legal guidelines for the type of training that investigative police officers should receive, their implementation varies significantly from state to state. The law requires that investigative police officers complete a five-to-six-month initial training course including on investigative techniques and legal theory. States are responsible for designing and providing this course, but they must submit their curriculum to the SESNSP—the federal body that sets security and justice training standards—for approval.
As of April 2024, nine states did not provide an approved training course for investigative police officers, according to information provided to Human Rights Watch by the SESNSP. Among those states that do provide an approved training course, less than half reported that 100 percent of officers had completed the course by the close of 2022, according to the national prosecutorial census.
Like state and municipal police officers, investigative police are also required to obtain a police certificate (CUP) every three years, requiring 40 hours of training, including 8 hours of training on investigative methods. In 2022, the percentage of investigative police officers who held a valid CUP varied significantly from state to state. In Guerrero, for example, only 17 percent of officers held a valid CUP.
The investigative police officers Human Rights Watch interviewed said that, despite being assigned to homicide or femicide units, they had received no additional training related to investigating homicides or femicides beyond the general training that all investigative police officers receive. Many said that they had participated in regular training courses throughout their time as investigative police, but that this training rarely focused on investigative methods. Some expressed a desire to receive more training on how to work with digital and scientific evidence. One said:
We take a lot of training courses, but they are mostly about what not to do. We get the same human rights training over and over. Most of us can recite it from memory. And we get training on the use of force. A lot of times the training is someone explaining a specific law. They just read the text of the law to us. But we don’t really get training on investigation. I would love to get that kind of training. Or a training on technology—like how to use phone records in an investigation.
Prosecutors
Prosecutors lead all criminal investigations in Mexico. A combination of extremely high caseloads, poor incentives, ineffective coordination with investigative police and forensic technicians, and inadequate training undermines prosecutors’ ability to conduct timely and robust investigations. In many cases, prosecutors simply do not have time to take basic steps to follow up on every case they are assigned and send requests for subsequent acts of investigation. Many prosecutors also pointed out that simply having enough time to issue timely instructions to investigative police and forensic and criminology technicians is not sufficient to solve crimes. As one legal advisor from a state victims’ commission said:
Prosecutors’ role isn’t just about ordering specific investigative acts. Prosecutors need time to analyze the evidence, think about theories of the case, and discuss them with their colleagues. Right now, that’s just not something they have time to do.
High Caseloads
Nearly every prosecutor, investigative police officer, legal advisor, or other expert interviewed for this report agreed that high caseloads are one of the main challenges limiting prosecutors’ ability to effectively follow up on cases.
Of the around 15,000 prosecutors working at state prosecutors’ offices nationwide, about 590 were assigned to units dedicated to investigating homicides in 2022. In the table below, Human Rights Watch attempted to calculate the number of new intentional homicide investigations and prosecutions per homicide prosecutor in 2022 in each state with a homicide unit.
|
Intentional Homicide Investigations Opened and Cleared per Prosecutor, 2022 |
|||
|
State |
Prosecutors in Homicide Unita |
New Intentional Homicide Investigations per Prosecutor |
Intentional Homicide Prosecutions Opened per Prosecutor |
|
Aguascalientes |
6 |
12 |
8 |
|
Baja California |
40 |
74 |
11 |
|
Baja California Sur |
5 |
9 |
3 |
|
Campeche |
Does not have a homicide unit. |
||
|
Coahuila* |
17 |
8 |
1 |
|
Colima |
9 |
82 |
2 |
|
Chiapas |
8 |
55 |
19 |
|
Chihuahua |
78 |
23 |
7 |
|
Mexico City |
54 |
18 |
12 |
|
Durango* |
8 |
14 |
6 |
|
Guanajuato* |
35 |
75 |
6 |
|
Guerrero |
7 |
162 |
10 |
|
Hidalgo |
8 |
38 |
9 |
|
Jalisco |
No information available. |
||
|
Mexico State* |
102 |
22 |
4 |
|
Michoacán |
51 |
41 |
15 |
|
Morelos* |
12 |
132 |
12 |
|
Nayarit* |
3 |
52 |
32 |
|
Nuevo León* |
22 |
60 |
18 |
|
Oaxaca |
8 |
104 |
5 |
|
Puebla |
29 |
31 |
7 |
|
Querétaro |
27 |
10 |
4 |
|
Quintana Roo |
Does not have a homicide unit. |
||
|
San Luis Potosí |
No information available. |
||
|
Sinaloa |
22 |
23 |
4 |
|
Sonora* |
11 |
149 |
11 |
|
Tabasco* |
10 |
29 |
9 |
|
Tamaulipas |
No information available. |
||
|
Tlaxcala |
8 |
16 |
6 |
|
Veracruz |
Does not have a homicide unit. |
||
|
Yucatán |
11 |
4 |
3 |
|
Zacatecas* |
10 |
100 |
11 |
|
a Number of prosecutors in state homicide units according to information provided by state prosecutors’ offices in response to information requests by Human Rights Watch (see Appendix I for a complete list of information request numbers). In the case of states marked with an asterisk (*), prosecutors’ offices did not provide useful information and the number shown is from the national prosecutorial census (CNPJE 2023). b Based on the number of new intentional homicide investigations opened in 2022 (INEGI, CNPJE 2023). c Based on the number of new court cases opened for intentional homicide in 2022 (INEGI, CNIJE 2023). |
|||
Homicide prosecutors’ true workloads are, in most cases, much higher than these numbers. In many states where Human Rights Watch conducted research, prosecutors in the homicide unit said that, in addition to intentional homicide cases, they were also responsible for investigating many related types of crime, such as attempted homicide, assault, femicide, “disappearance,” and unintentional homicide. In some states, they said, these types of cases accounted for the majority of their workload. These numbers also do not include pending court cases or unsolved investigations opened in previous years, which, in most states, significantly outnumber new investigations.
For example, in Sinaloa, the state prosecutor’s office opened 512 new intentional homicide investigations in 2022—around 22 per prosecutor. But, in 2022, the state also reported having 6,521 unsolved intentional homicide investigations pending from previous years, meaning that the true number of unsolved homicide cases per prosecutor in 2022 was around 320. In Chiapas, factoring in pending unsolved homicide investigations from previous years works out to 254 pending homicide cases per prosecutor. In Nuevo León, adding in assault cases, which homicide prosecutors there also investigate, increases the number of pending investigations per prosecutor in 2022 from 60 to 971. That still does not include unsolved intentional homicide investigations from previous years. However, Nuevo León was one of ten states where authorities told Human Rights they were not able to determine how many unsolved intentional homicide investigations were pending from previous years. Many of the prosecutors interviewed for this report were also unsure of how many unsolved cases were pending in their states.
There is no nationally or internationally accepted standard regarding the maximum number of cases that a homicide prosecutor can effectively investigate in one year. However, for comparison, the United States Department of Justice recommends that homicide investigators should be given no more than six new investigations per year.
Ineffective Prioritization of Cases
Despite prosecutors’ high caseloads and limited capacity, many of the current and former prosecutors interviewed for this report did not describe working with any type of clear or objective framework to determine which cases to prioritize. Instead, prosecutors and legal advisors said they usually end up prioritizing three types of cases: urgent cases (in which police have detained a suspect without a warrant, meaning authorities have a limited time to present criminal charges), simple cases (meaning a member of the victim’s family has agreed to provide testimony that would be sufficient to obtain a vinculación a proceso), and politically relevant cases (meaning those that are generating negative media attention for the prosecutor’s office or the government).
As one legal advisor from a state victims’ commission said:
In my experience, there are two types of cases. If a case is getting a lot of media attention, or the victim is someone important, then prosecutors will treat it as a priority. Otherwise, it’s a “normal” case. That means that, unless the victim’s family is pressuring them to investigate, they probably won’t do much.
Another legal advisor, who had previously worked as a prosecutor, added:
It’s not that prosecutors don’t want to keep investigating. It’s just that there are so many cases. The reality is, if you have 10 cases sitting on your desk, and a victim shows up asking you to take action, that’s the case you’re going to work on.
Lack of Specialized Training on Homicides
Another factor that can limit prosecutors’ ability to effectively investigate more complex cases is a lack of opportunities for specialized training. As with other justice operators, federal law requires that all prosecutors complete an initial training course, provided by their state prosecutor’s office, that has been reviewed and approved by the SESNSP, the federal agency that sets security and justice training standards.
However, as of April 2024, 14 states did not even offer an initial training program for prosecutors that met federal training standards. Even among those states that do provide an approved program, four reported that none of their prosecutors had completed it at the close of 2022 and in three others, less than a quarter of prosecutors had completed the training.
Some prosecutors told Human Rights Watch that they often relied on witness testimony to investigate cases because they feel they don’t have the time or training to use other types of evidence, like digital and scientific evidence. One said:
The truth is that, in the past, under the traditional system we always just relied on witnesses. I feel that, now, we still don’t really know how to work with scientific evidence. We should be using things like phone geolocation and genetic analysis. But we’ve never received any training on working with that kind of evidence and there’s not a lot of time for it.
A Human Rights Watch researcher later attended a vinculación a proceso hearing in a femicide case in the same state. During the hearing, the judge expressed concern that prosecutors had based their arguments largely on witness testimony and reminded them that, if they wanted to demonstrate that the defendant had been present at the time and place of the victim’s killing, they could do so more conclusively by requesting a court order to obtain the geolocation data from the defendant’s mobile phone.
Poor Coordination
Poor coordination between prosecutors, investigative police officers, and forensic technicians can undermine homicide investigations, leading to omissions and delays. This is caused by a range of factors, described below.
Overly Bureaucratic Communication
Typically, when a case is opened, it is assigned to an individual prosecutor who is responsible for analyzing the initial report from the crime scene and any accompanying evidence or information that investigative police and forensic technicians have recovered, identifying possible theories of the case, and deciding which lines of investigation to pursue. To follow up on cases, prosecutors issue written instructions, in long, extremely formal legal documents (known as oficios), which are sent to the head of the investigative police or forensic services department, asking them to assign an officer or a forensic technician to conduct specific additional acts of investigation or forensic studies.
In most states, these written instructions must be printed, signed, and sent on paper to their recipient, before being added to a paper case file to serve as a record of each individual act of investigation that was requested. Once the specific act of investigation or forensic study has been assigned to an investigative police officer or forensic technician and completed, the officer or technician who conducted the study or act of investigation writes a report with their findings, which, typically, must also be printed, signed, and sent on paper back to the prosecutor in charge of the case, who will add it to the case file. In some states, parts of this process have been made electronic, which usually means that the document is sent by email, although in many of these states, it must still be printed out to be saved in the case file, since most states do not have an electronic record-keeping system.
This way of coordinating investigations, by ensuring that a written legal justification is issued for each act of investigation before it is conducted, was the rule in Mexico prior to the 2008-2016 justice system reform. However, under the current National Code of Criminal Procedure (CNPP), adopted in 2014 as part of the transition to the adversarial system, this requirement no longer exists. The CNPP only requires that investigative police officers make a record of all acts of investigation they conduct and evidence they obtain, and grants judges the discretion to independently evaluate the validity of each piece of evidence in relation to the case as a whole.
In many states where Human Rights Watch conducted research, officials acknowledged that this way of coordinating investigations and communicating with their colleagues was inefficient. However, they typically cited three reasons for working this way. First, some prosecutors said they feared that, if they are unable to show written instructions providing a legal justification for each act of investigation when appearing in court, or if the instructions do not provide the correct legal justification, any evidence obtained through that act of investigation may be excluded by the judge. As one prosecutor said:
Every judge seems to have their own criteria about these things. It’s better to have more documentation just to be safe.
Second, they said, requesting each act of investigation individually in writing can be useful as a way of keeping a record of these requests in case they are later required to prove that they followed up on the case in a timely manner. And third, they said, most other government agencies, such as public safety departments and public health institutions, will not provide information or cooperate with an investigation unless they are given a physical document providing a legal justification for the request.
One problem with this way of coordinating investigations is that, for the most part, once the initial steps of the investigation have been completed, no additional steps are taken unless they are specifically requested in writing by the prosecutor leading the case. As a result, prosecutors and legal advisors said, many cases are simply ignored until a family member comes to the prosecutor’s office to ask for information.
The focus on paper-based communication and emphasis on the formal separation between prosecutors, members of the investigative police, and technicians in the forensic services department can seriously limit coordination between different people working on the same investigation. As one prosecutor explained:
In our state, the investigative police can’t tell us anything without permission from their commanders. When we arrive at the crime scene, they are already there collecting evidence, conducting interviews, getting security camera videos. But if we ask about what they’ve found, they say, “I need to send it to my boss first. You’ll get a written report later.” That could take days. It can really delay the whole investigation. There is a lot of secrecy about what they do and what they are willing to share with us.
In another state, a forensic technician, who is usually assigned to respond to crime scenes, expressed a similar sentiment:
After a case is opened, and I have filed my report on the crime scene inspection, I probably won’t hear about it again. There has never been a meeting with everyone involved in the case to discuss possible lines of investigation. I’m often the first person at the crime scene after the local police. I see a lot of details firsthand. But no prosecutor has ever asked me for my thoughts on a case.
This lack of coordination does not just undermine investigations. It can also lead to problems if a case goes to trial and the local police officers, investigative police officers, or forensic technicians who participated in the investigation are called to testify about a case they worked on years prior. As one former forensic technician explained:
Everyone is working on their own part of the case. But you never know what’s happening with the rest of the case. People are very jealous of the information they have. There were a lot of conflicts in my state between prosecutors and forensic technicians over court hearings. They would tell us maybe a day in advance that we had to testify. But they didn’t want to give us copies of the case file to prepare. And these are cases you worked on maybe three years ago. There’s no way to remember the details without reading the case file. We often ended up arguing with the prosecutors, saying “If you don’t give me a copy of the case file in advance, I will not show up in court and your case will fall apart.”
Atomized Approach to Investigation
Not all states have a clear system for determining which cases or acts of investigation are assigned to which investigative police officers. Requests to conduct acts of investigation are directed to the chief of the investigative police or to the director of forensic services. Officers may be given responsibility for a case as a whole or may be assigned to carry out individual investigative tasks related to multiple cases. Multiple investigators and forensic technicians may be assigned to carry out different parts of the same investigation.
This can lead to investigative police officers being assigned to carry out individual investigative tasks from multiple investigations despite having limited prior knowledge of each case. Some prosecutors and legal advisors said they have come across cases in which investigative police officers have failed to ask relevant questions in interviews or failed to notice relevant pieces of evidence, which they suspected was because the officers who had been assigned to conduct those specific tasks were not familiar with the details of the case. As one legal advisor from a state victims’ commission explained:
It’s very common to find witness interviews in our case files that are technically correct but leave out a lot of relevant information. The officers take a person’s statement, but they don’t know what questions to ask. They just say, “tell me what happened.” Later, when we are talking with family members about the case, they mention important details that they say they brought up in their interview, but that the officer didn’t write down in the final statement.
The lack of a clear system in some states to determine which investigative police officer is responsible for which case or investigative task can also make it more difficult for victims’ families and their legal advisors to follow up on cases. As one legal advisor from a state victims’ commission explained, not knowing who is responsible for conducting a pending interview, for example, can make it harder to take action to prevent delays in the investigation:
In our city, they tried creating specific groups within the investigative police: the robbery group, the homicide group, etc. So, when there was a delay in doing something, like conducting an interview or requesting security camera footage, we could send a written reminder to the head of that group on behalf of the family. But they never really followed that system, and they ended up getting rid of it. Now, we send a request to conduct an investigative act, and we don’t know who it has been assigned to. Even if we ask, they don’t want to tell us. Weeks or months can go by. The family says, “they still haven’t interviewed my neighbor,” but we don’t know who to follow up with. It’s easier for them to ignore us that way.
Efforts to Improve Coordination
In recent years, many states have taken steps aimed at improving coordination in intentional homicide investigations. As of 2022, almost every state had established a special prosecutor’s office or a specific unit for investigating homicides, although their mandates vary from state to state. In 16 states, prosecutors’ offices reported, either in the national prosecutorial census or in response to an information request by Human Rights Watch, that there were investigative police officers specifically assigned to their specialized homicide units.
In some of the states where Human Rights Watch conducted interviews, there was a specialized unit responsible for investigating homicides with investigative police officers and crime scene technicians specifically assigned to it. Prosecutors in these states said they believed that adopting this model had helped improve coordination, making their investigations more efficient. However, prosecutors and investigative police officers from these units said that they did not receive specific training related to homicide investigations. And some prosecutors said that frequent turnover in the assignment of investigative police officers to their homicide units undermined investigations, since more experienced investigative police officers were often replaced with newer ones.
In the states where prosecutors reported that adopting this structure had been most effective, prosecutors’ offices had not only assigned specific investigative police officers and forensic technicians to homicide units, but they had also adopted specific strategies to promote communication and coordination between these three groups. In these states, prosecutors said that they coordinated directly with the investigative police officers and forensic technicians assigned to each case, rather than through the heads of each department. Prosecutors said that the standard practice in these states is for the prosecutors, investigative police officers, and forensic technicians who responded to the initial crime scene to hold a meeting after the investigation has been opened or to hold regular meetings to discuss the status of pending cases. As one prosecutor explained:
We work with a concept called the “trilogy of the investigation”—prosecutors, investigative police, and forensics. From the moment we receive a report of a homicide, we are discussing the hypothesis of the case. We try to have a meeting as soon as possible after the crime scene has been processed to discuss the evidence and the next steps. Our goal is always to identify a suspect within 48 hours. I would say we achieve that goal in 9 out of 10 cases.
The same team deals with the case from start to finish. And we keep personal notebooks to record our thoughts on the case and decide which acts of investigation to conduct, so we’re not relying on looking at all the documents in the case file. It helps that we are all in the same building, so we know each other, we talk regularly, and we can make sure the investigative police officers and forensic technicians working on complex cases are people with more experience, not just for the investigation, but also because they have experience testifying in court.
Most homicide investigations in Mexico do not advance beyond the initial stages. A case file is opened, including the initial information obtained from the crime scene and any acts of investigation conducted in the beginning of the case, but, usually, no suspect is ever formally identified, no arrest warrant is requested, and no criminal charges are presented. In 2022, for example, state prosecutors’ offices opened around 28,700 intentional homicide investigations (not including femicides) but formally identified a suspect and requested an arrest warrant, or citation or presented criminal charges in just around 5,300 cases—equivalent to around 18 percent of the cases opened that year.
The prosecutors, investigative police officers, and legal advisors from state victims’ commissions interviewed for this report described a range of failures that take place in the initial stages of investigations. In some cases, police or forensic technicians commit errors or omissions when responding to the crime scene or when processing evidence, which can make it more difficult for prosecutors to identify a suspect and present criminal charges. There are also often serious delays in conducting interviews and collecting key pieces of evidence once an investigation has been opened. In some cases, there are delays in identifying victims, which can lead to delays in conducting other acts of investigation. In other cases, prosecutors cannot identify the victim and do not move forward with other parts of the investigation.
Delays and Errors Responding to Crime Scenes
Many of the prosecutors, forensic technicians, investigative police officers, and legal advisors interviewed for this report said that failures to adequately preserve and process crime scenes can lead to evidence being contaminated or lost, which can make it difficult to build a criminal case. As one legal advisor from a state victims’ commission explained:
When cases come to us, they have usually already been open for a year or two. Sometimes, when we get access to the case file, we see that the investigators never took photos of the crime scene. Or they did but they didn’t take samples of the blood spatter or dust for fingerprints, or they didn’t notice a murder weapon lying nearby. You can’t fix an error like that after two years. The evidence is gone.
Many legal advisors and private lawyers who represent victims of crime described cases in which the investigative police officers and crime scene technicians who responded to the initial crime scene had failed to collect key pieces of evidence, leading to problems later on. One private lawyer described such a case:
I recently represented a woman whose ex-boyfriend had broken into her house and tried to kill her with a knife. When the crime scene technicians came to her home, she tried to give them the clothes she had been wearing when she was attacked so that they could examine the blood stains, but they told her it wouldn’t be necessary. Later, the prosecutors told us they couldn’t move forward with the case because, without an analysis of the blood stains on the victim’s clothes, they couldn’t demonstrate the mechanics of the attack. I’ve seen many cases that don’t move forward for reasons like this.
Some forensic technicians said that these types of errors are the result of high workloads and a lack of basic equipment necessary to collect and preserve evidence. As one former crime scene technician explained:
When I worked as a crime scene technician, we had no system for storing evidence in the truck. The investigative police in our state were supposed to come to the crime scene and bring the evidence directly back to the forensic laboratory. But often, they were busy doing other things, so we would go from crime scene to crime scene, putting all the evidence in the back of the truck. At the end of your 24-hour shift, you had a trunk full of evidence from all these different crimes. It’s very easy for evidence to get mixed up or contaminated. People focus on what happens in the laboratory, but I think a lot of the problems happen before it even gets there.
Another crime scene technician in a different state, said:
Of course, you try to do everything correctly. But by the time you are responding to your third event of the night, you’re just tired. And usually there are multiple events back-to-back. You’re processing one crime scene, and you get a call to respond to another. So, you rush to get everything done quickly so you can get to the next crime scene because you know that the longer you wait, the more likely it is the evidence gets contaminated. We work four days on, four days off. But even on your days off, you’re not really off. You’re at the office writing reports on the evidence you collected while you were on shift.
Delays in Processing Evidence
Even when all the relevant evidence has been collected from a crime scene and returned to the crime lab, some forensic technicians said that their high caseloads can make it difficult for them to dedicate sufficient time to each case. This can lead to delays and backlogs in processing evidence.
As one former fingerprint technician explained:
We always had an enormous backlog of evidence to process and reports to write in my state. If a case was high priority, like if it was a femicide or it was politically relevant, I would try to rush processing the evidence and get the report written in two weeks. But for most cases, it would take a month or more before I could do the analysis and write the report.
Another said:
It’s very frustrating. The prosecutors are always complaining that we take too long to process the evidence. But we don’t have enough people. And to make things worse, they are often taking people out of the crime lab to send them out to work as crime scene technicians because there are never enough people to respond to crime scenes.
Delays in processing evidence when a case is first opened can have serious consequences for the rest of the investigation, some legal advisors from state victims’ commissions said. This is because prosecutors and investigative police officers often wait until the evidence recovered from the crime scene has been processed and the victim has been identified to take the next steps in the investigation, such as interviewing the victim’s friends and family.
In other cases, legal advisors said, even when relevant evidence has been collected, prosecutors may simply choose not to ask forensic technicians to analyze it because they believe doing so would cause delays in their case or they simply want to avoid contributing to the backlog in their state’s forensic laboratory. Two Legal advisors, from different states, described cases in which crime scene technicians had collected a piece of evidence with blood stains on it, but decided to present it as evidence without conducting any forensic testing.
In one of the cases, a legal advisor said, prosecutors had obtained a knife, which they believed to be the weapon used in a murder, but decided not to test the knife for fingerprints to see if they matched the suspect in the case or test the blood on the knife to confirm it belonged to the victim because they believed conducting forensic testing would lead to unnecessary delays. In another, investigative police had found blood stains on the defendant’s shoes. They presented the shoes in court as a key piece of evidence. But they never had the blood on the shoes tested to confirm that it belonged to the victim. The case ended in a not-guilty verdict.
Errors in Forensic Studies
Forensic technicians, prosecutors, defense attorneys, and legal advisors from state victims’ commissions said that they sometimes find basic errors in the forensic studies included in the cases they work on, such as autopsy reports, DNA tests and blood tests with errors like the wrong victim’s name, the wrong date, or the wrong cause of death. One former forensic technician said that he believed many of these errors are the result of technicians rushing to keep up with high caseloads, which can often mean copying and pasting information from one report to another, or even fabricating test results:
Forensic reports are very long and bureaucratic in Mexico, so for a lot of them, it’s easier to use a kind of template and just swap in the details of your specific case. But often, you’re in a rush. You’ve worked a 24-hour shift out in the field and now you’re at the office trying to finish your paperwork so you can go home. You forget to change the victim’s name, or the cause of death, or you accidentally leave in the test results from a different case. We all do it.
Then, in other cases, when there’s just too much work, and the prosecutors are pressuring you to get everything done, sometimes it’s easier to just fake the whole study. Like if you know the prosecutors think the powder they found is cocaine, and they’re waiting for you to confirm. You can just go online and find a chemical analysis of cocaine and copy and paste it into your report.
Legal advisors from state victims’ commissions said it was common for them to find forensic studies included in the cases they worked on that appeared to include information that had been erroneously copied from other cases. Often, they said, it could be expensive and time-consuming to try to fix these errors retroactively. One said:
Victims come to us wondering why the prosecutor’s office hasn’t moved forward with the case. When we get a copy of the case file, we often find serious errors in the forensic studies. Like the autopsy report says the victim was strangled, but the family says they were actually stabbed. Or femicide cases where the medical examiner somehow didn’t realize that the victim was pregnant. Sometimes the reports have the wrong date or the wrong victim’s name. We’ve had to exhume bodies to have new studies done by private forensic labs. It’s not just inefficient, it’s revictimizing for the families.
Failure to Identify the Victim
In many states, limited human identification capacity prevents authorities from effectively investigating murders. According to the most recent prosecutorial census conducted by the national statistics agency, of the around 100,000 human remains examined by forensic authorities in 2022, nearly 20,000 were never identified, including 3,795 suspected intentional homicide and femicide victims (around 11 percent of all murders that year), 1,285 victims whose cause of death could not be determined, and 9,231 whose cause of death had yet to be determined. A recent investigation by journalists from Quinto Elemento Lab found that, from 2006 to 2023, more than 72,000 human remains were declared as unidentified by state forensic authorities. Due to limited storage capacity in most states, the majority of unidentified remains were buried in municipal mass graves, journalists found. And according to the prosecutorial census, of the around 20,000 human remains that were not identified in 2022, just 3,681 were placed in storage for future identification.
Additionally, even when authorities do eventually identify victims, there can be significant delays, some legal advisors from state victims’ commissions said, especially in cases where the victim’s remains have been dismembered, begun to decompose, or were recovered as skeletal remains from a clandestine grave. In these types of cases, where simple visual identification by a family member is difficult or impossible, the Minnesota Protocol on the Investigation of Potentially Unlawful Death recommends that “any identification by visual recognition must be confirmed, whenever possible by using other means, including scientifically reliable methods of identification such as fingerprints, dental examination, and DNA analysis.”
However, many state justice authorities have extremely limited capacity in fields like forensic anthropology, archaeology, dentistry, radiology, and genetics. In 2022, 12 states reported they did not employ a forensic anthropologist, required to analyze skeletal remains. Twenty-eight did not employ a forensic radiologist, required to conduct imaging studies such as X-rays. And six did not employ a forensic dentist, who can play a key role in using dental records for identification.
Delays in determining victims’ identity and cause of death can lead to critical delays in the rest of the investigation since, as discussed in more detail later in this report, authorities typically rely heavily on information from victims’ family members to investigate murders. As one legal advisor from the office of a state victims’ commission covering a large rural area far from his state’s capital explained:
Often, after they recover a body, it can take months to actually open a homicide investigation because the prosecutors are waiting until the victim has been identified. It’s very hot here and bodies decompose and become unrecognizable very quickly, which can make identification more difficult. I had a case last year where the victim was found on a farm. If she had been identified immediately, they probably would have conducted a detailed inspection of the crime scene or tried to interview people who lived nearby. But it took three months for the disappearances unit to identify the victim and transfer the case to homicides. By that point, the farmer had already tilled the field and planted his crops. The evidence was gone.
Delays in Following Up on Cases
Once the initial crime scene reports have been filed and the evidence recovered from the crime scene has been processed, there are often serious delays in taking subsequent investigative steps, such as identifying and conducting interviews with additional witnesses or obtaining video footage from nearby security cameras. In many cases, prosecutors, investigative police officers, and legal advisors said, these delays are the result of high caseloads. It may take weeks for the prosecutor in charge of the investigation to have time to review the case file, decide which investigative steps to take next, and write and send instructions to the investigative police or information requests to other authorities. Once the instructions have been sent to the investigative police, it can take even longer for an officer to be assigned to conduct the specific investigative act and carry it out, according to interviews with prosecutors and legal advisors and case files reviewed by Human Rights Watch.
This can be particularly problematic when dealing with evidence that is deleted after a certain period of time, such as cell phone GPS records, which can be obtained with a court order and used to determine a suspect’s location at the time of the homicide, or video footage from security cameras, which could show the suspect in the area or be used to identify witnesses. For example, many investigative police officers and prosecutors said they rely heavily on video footage from the closed-circuit camera systems operated by their municipal and state public security departments as evidence in homicide cases, especially when witnesses are unwilling to provide written testimony or appear in court. Typically, they said, this camera footage is only preserved for a set period of time, usually two to four weeks.
In one case, which Human Rights Watch was able to review in detail, the process of requesting and obtaining this camera footage involved more than 20 letters, reports, and other documents and took more than three months, by which time most of the relevant videos had been deleted. To illustrate the nature of these delays, the following is an abridged timeline of this process, based on documents from the case file and an interview with a member of the victim’s family. Dates have been removed to protect the anonymity of the family.
Day 1: Victim is reported missing.
Day 14: A body is recovered matching the victim’s description.
Day 15: Prosecutors send a letter to the investigative police, asking for an officer to be assigned to go to the location where the body was recovered and identify any security cameras that could have recorded relevant events.
Day 28: The investigative police officer assigned to look for security cameras at the crime scene sends a report to prosecutors with a list of camera locations and photos of each security camera. Prosecutors immediately send letters to the state and municipal public security departments asking for access to any recordings from these cameras from days 1-14.
Day 33: The state public security department replies to prosecutors’ letter. They say they only keep 30 days of recordings in their system but can provide videos from day 3 onwards. They recommend prosecutors send someone with a USB drive to collect the recordings urgently before they are automatically deleted.
Day 34: The municipal public security department replies to prosecutors’ letter. They say their system only holds approximately 15 days of recordings, but that they still have videos from days 13 and 14. They recommend prosecutors send someone with an external hard drive to collect the recordings urgently, before they are automatically deleted.
Day 46: Prosecutors send a letter to the investigative police asking for an officer to be assigned to go pick up the recordings from the state and municipal public security departments.
Day 48: The municipal public security department sends a letter to prosecutors saying the recordings mentioned previously have now been deleted, since they only keep 15 days of recordings.
Day 57: The investigative police officer assigned to go pick up the video recordings from the municipal public security department sends the prosecutor a 5-page report explaining that he went there and found there were no recordings available, since they are automatically deleted after 15 days.
Day 75: Prosecutors send another letter to the investigative police asking for an officer to be assigned to go back to the municipal public security department to see if there are video recordings from days 1-14 from an additional 9 security cameras identified near the crime scene.
Day 83: The state public security department replies to the prosecutors’ letter, sent on Day 15, attaching a USB drive with recordings from two cameras.
Day 85: Prosecutors send a letter to the technical analysis unit of the investigative police, asking them to assign an officer to review the recordings provided by the state public security department.
Day 98: The investigative police officer assigned to go to the municipal public security department to look for the additional 9 recordings sends the prosecutor a 6-page report saying he went there and found there are no recordings from the time of the murder, because they are deleted after 15 days.
Day 98: The investigative police officer assigned to review the two recordings provided by the state public security department sends prosecutors a letter saying he found nothing relevant in the recordings.
The case remains unsolved. In an interview, the legal advisor representing the victim’s family told Human Rights Watch that prosecutors had told her they did not expect the case to be solved since “there are a lot of criminals” in the neighborhood where the victim lived.
The legal advisors, lawyers from human rights organizations, and private lawyers interviewed for this report all described many similar cases, in which it took prosecutors months or even years to conduct extremely basic investigative steps, or in which prosecutors appeared to be conducting these steps as a formality, despite being aware they would no longer be of any use in the investigation (such as sending an officer to collect video recordings that prosecutors knew had already been deleted).
Victims’ family members and other witnesses are often reluctant to cooperate with investigations, usually because they fear facing retaliation by the friends, family, or associates of the accused. Prosecutors rely heavily on witness testimony to build criminal cases. But they often fail to provide adequate protection for witnesses, leading many to refuse to participate or to withdraw from the investigation after being threatened or attacked.
Fear of Retaliation
In the initial stages of an investigation, investigative police interview witnesses, and typically ask them to sign a formal written declaration to be included in the case file. If prosecutors identify a suspect and decide to initiate criminal proceedings, the statement made in this declaration can be used as evidence at the initial hearing, to seek a vinculación a proceso. These written declarations include the full name and address of the witness and, along with the rest of the case file, they are made available to the victim’s family and to any defendants in the case. If a case proceeds to trial, the witnesses who made signed declarations will be asked to appear in court to testify before the judge, the defendant, and the representatives of the victim.
Most investigative police officers and homicide prosecutors interviewed for this report said that the primary reason most cases do not move beyond the initial investigation is that they are usually unable to convince people with information about a murder to sign a written declaration. In many cases, they said, witnesses fear that once their name and other personal information is shared with the defendant, they may face retaliation, such as threats, assault, or even attempts on their life. This fear is particularly common in cases where either the victim or the defendant is suspected of having links to organized crime. As one former prosecutor explained:
When we deal with cases related to a one-off killing, like a bar fight, usually we can manage to get a witness to testify. The main problem is killings related to organized crime—and that’s most of the cases we deal with. Anyone who knows anything in those cases is afraid to put their name on a witness statement. Even the victims’ families don’t want to talk. They are afraid of being attacked or killed. Even when we offer to let them speak to us anonymously, people are afraid the information could be traced back to them.
In some cases, people with relevant information are willing to share it with investigators anonymously, many investigative police officers said. While this kind of information could, in theory, be useful to help investigators identify new lines of investigation or locate relevant physical evidence, in practice, both investigators and prosecutors are often dismissive of information obtained from witnesses who are unwilling to sign a declaration. As one homicide prosecutor put it:
If it’s not an official, signed witness statement, then as far as I’m concerned, it’s just a rumor. Often, a police officer or an investigator comes in and says, “Hey, we found out something important.” But they don’t have a signed witness statement. That’s not useful to me. It’s not about what I know; it’s about what I can prove. The only thing that matters is if someone will testify in court. If I don’t have that, who cares?
In many cases, prosecutors, legal advisors, and investigative police officers interviewed for this report said, people who believe they might be asked to provide testimony in murder investigations go to great lengths to avoid speaking with the authorities, usually out of fear. They often refuse to answer the door when investigators come to their homes, change their phone numbers, and sometimes go as far as to abandon their homes or businesses and move to a different city or state.
Prosecutors, investigative police officers, and legal advisors also described numerous intentional homicide and femicide cases they had worked on that had fallen apart after the main witness was threatened or attacked. In one case, described by a legal advisor:
I represented a man a few years ago in a case for kidnapping and homicide. He and his friend had been kidnapped. The kidnappers murdered his friend, but he survived. He agreed to sign a declaration and testify against the kidnappers. With the man’s signed declaration, the prosecutors were able to get an arrest warrant for the people he had accused. But because his name was on the declaration, the defendants knew he was the one who was going to testify against them. They started calling him from jail saying if he testified in court, they would have him killed. We offered him protection, but he refused. He fled to a different state and told prosecutors he would no longer participate in the trial. Without his testimony, the judge said there was not enough evidence, and the defendants were released.
This problem is exacerbated by overall low levels of trust in police and prosecutors among most members of the public, which prosecutors said makes many people reluctant to share information. It is also compounded by prosecutors’ tendency to build cases primarily or exclusively on the testimony of just a few witnesses, with limited physical evidence, which can in turn heighten the incentives for perpetrators to threaten or attack witnesses.
In many cases described by prosecutors, investigative police officers, and legal advisors, witnesses signed a written declaration and agreed to testify in court but were then killed or disappeared to prevent them from participating in the trial. Nearly everyone Human Rights Watch interviewed described cases they had worked on that had been dismissed or otherwise fallen apart after a witness had been killed to prevent them from testifying. An investigative police officer interviewed described one such case:
I investigated the killing of a young man. His parents knew what had happened. They told us their son had stolen from a group of local drug dealers, and they had murdered him in retaliation. The parents gave us signed declarations naming the defendants and we arrested them and charged them with murder. Then, maybe a year later, the date of the trial is coming up and they killed the mother. The father contacted us and said, “They killed my wife, so I’m not going to testify anymore.” The prosecutor asked me to find him and speak to him, to see if we could convince him to change his mind and explain that we can offer protection. But he ran away. He moved to a different house and changed his phone number, so the case ended up being dismissed.
Ineffective Protection
Given the high level of risk that witnesses in murder cases often face in Mexico, witness protection measures play a crucial role in ensuring effective investigations and prosecutions.
Mexico’s National Code of Criminal Procedure (CNPP) requires all state prosecutors’ offices to provide protection for witnesses in criminal cases or for other people who may be at risk due their involvement in criminal investigations, such as victims’ families. Most states have also established similar requirements in their state laws, either in the organic law of the state prosecutor’s office or by passing a state witness protection law.
In practice, however, protection for witnesses can often be both difficult to obtain and ineffective. One major reason is that most states have not taken the necessary steps to implement the protection systems required by state and federal laws.
In 24 states, there is a state law requiring the prosecutor’s office to establish a specific unit or department responsible for coordinating protection for witnesses, victims of crime, their family members, or other people who may be at risk. Under most of these states’ laws, when prosecutors or investigators believe a witness or victim may be at risk, they can file a request with the protection unit, which should conduct an analysis to determine whether and what type of protection measures would be appropriate.
However, when Human Rights Watch asked state prosecutors’ offices for information about these protection units, only three states confirmed that such a unit exists and had staff assigned to it: Chihuahua, Michoacán, and Tabasco. Three others, Querétaro, Nuevo León, and Tamaulipas, said that their offices had staff who were responsible for analyzing and following up on requests for protection.
Compounding this problem, while some state prosecutors’ offices have established at least a rudimentary system for determining when and how to provide protection measures for victims of crime, few state prosecutors’ offices regularly extend these protections to witnesses, despite being required to do so by state and federal laws. In one state, legal advisors from the state’s victims’ commission said that, when they have attempted to secure protection measures for witnesses, prosecutors have falsely told them that “protection measures are for victims, not witnesses.”
As the chart below illustrates, just 14 states reported providing protection measures to witnesses in criminal cases in 2022.
|
State |
Witnesses Protected in 2022
|
Types of protection provided |
|
|
All Crimes |
Intentional Homicide |
||
|
Aguascalientes |
No information available |
||
|
Baja California |
20 |
8 |
Police surveillance |
|
Baja California Sur |
4 |
4 |
Police surveillance |
|
Campeche |
No information available |
||
|
Coahuila |
No information available |
||
|
Colima |
No information available |
||
|
Chiapas |
No information available |
||
|
Chihuahua |
112 |
60 |
Relocation assistance, temporary shelter, police surveillance |
|
Mexico City |
No information available |
||
|
Durango |
No information available |
||
|
Guanajuato |
No information available |
||
|
Guerrero |
15 |
0 |
Police surveillance, restraining orders |
|
Hidalgo |
56 |
8 |
Temporary shelter, restraining order |
|
Jalisco |
No information available |
||
|
Mexico State |
Information is classified |
||
|
Michoacán |
742 |
48 |
Relocation assistance, temporary shelter, police protection, identity protection, creation of new identity, installation of home security equipment, provision of panic buttons |
|
Morelos |
Did not respond |
||
|
Nayarit |
Did not respond |
||
|
Nuevo León |
52 |
20 |
Temporary shelter |
|
Oaxaca |
1 |
0 |
Child placed in shelter |
|
Puebla |
18 |
7 |
Police surveillance |
|
Querétaro |
41 |
20 |
Police surveillance, restraining orders |
|
Quintana Roo |
Did not respond |
Did not respond |
n/a |
|
San Luis Potosí |
27 |
12 |
Police surveillance |
|
Sinaloa |
No information available |
||
|
Sonora |
2 |
Did not respond |
No info |
|
Tabasco |
0 |
0 |
n/a |
|
Tamaulipas |
6 |
6 |
Police surveillance |
|
Tlaxcala |
8 |
3 |
Police surveillance |
|
Veracruz |
No information available |
||
|
Yucatán |
0 |
0 |
n/a |
|
Zacatecas |
No information available |
||
|
Source: Public Information Requests filed by Human Rights Watch. See Appendix I for a complete list of information request numbers. |
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In most states, the measures offered are limited to police surveillance. In practice, this usually means that prosecutors send a request to the state or local police department asking for a police officer to visit a victim or witness’s home once or twice per day or provide a phone number the victim or witness can call if they need help. Prosecutors explained that these measures can leave people feeling unprotected.
Obtaining protection measures can be complicated and time-consuming, and many states may not have the facilities needed to provide them. One legal advisor from a state victims’ commission described the steps he had to go through to request protective custody for a victim in an attempted murder case:
I represented the victim of an attempted homicide. He had been attacked by the leader of the opposing cartel. He was going to testify against his attacker in court. Then, the members of the opposing cartel tried to kidnap his brother. When that didn’t work, they came to his house to try to kill him. We requested that the prosecutor’s office put him in a shelter until the trial was over. But the prosecutor’s office told us our state has no shelters for men, only women. I sent a request to the federal attorney general’s office, to see if they could help. They wrote back saying my request was incorrectly written, so they couldn’t process it. Finally, I spoke to the head of our state victims’ commission, who spoke to someone at the state’s public security department, who got special permission from the state Secretary of Public Security to place the man in a safe house managed by the state police department.
At times, protection measures are so burdensome that victims and witnesses prefer not to accept them and opt not to participate in the investigation. Some states offer the option of providing some kind of temporary protective custody for victims and witnesses who cannot remain in their homes for the duration of the trial. However, shelter space can be limited, uncomfortable, and inconvenient. As one prosecutor explained:
Legally, the Witness Protection Unit in our state is supposed to run a shelter for witnesses. But the unit doesn’t exist and neither does the shelter. The only thing we can offer is space in a dormitory in the basement of the prosecutor’s office. Not a lot of people want to live in the prosecutor’s office for six months, especially when they have to work and take care of their kids and everything else.
While only a small portion of intentional homicide investigations opened by state prosecutors’ offices in Mexico result in any kind of judicial action by prosecutors, when prosecutors do identify and arrest a suspect and present criminal charges, these cases usually lead to a verdict. In 2022, for example, state prosecutors formally identified a suspect and presented criminal charges in around 5,300 intentional homicide cases (not including femicides). That same year, judges in state court systems issued around 3,850 verdicts in intentional homicide cases, equivalent to around 70 percent of the prosecutions initiated. Around half were guilty verdicts issued following an oral trial. Another 28 percent were guilty verdicts issued through an abbreviated procedure.
Often these prosecutions are the result of criminal investigations that violate the rights of defendants and do little to ensure justice for victims. In some states where we conducted research, we found that investigators and prosecutors appeared to be focused on opening court cases as quickly as possible, rather than taking the time to collect and impartially verify all the relevant evidence to determine the truth about how a victim died, whether the victim’s death was unlawful, and who, if anyone, might be criminally responsible.
That can mean that prosecutors may move forward with opening criminal cases and requesting the pre-trial detention of suspects based on evidence that they know to be inaccurate or that would not be sufficient to obtain a guilty verdict if the case were to proceed to trial. It can also mean that, to meet their targets or strengthen weak investigations, authorities sometimes encourage victims’ family members or other witnesses to sign false or inaccurate witness statements, aimed at incriminating the person accused of the murder. Worse, it can lead to situations where authorities use threats, abuse, or even torture to coerce people into signing witness statements or agreeing to plead guilty to crimes in exchange for a reduced sentence.
These practices are often due, in part, to incentives within prosecutors’ offices, such as performance targets for investigators and prosecutors, that prioritize the number of suspects detained or arrest warrants issued, rather than conducting effective, rights-respecting investigations. They can also be the result of social or political pressure on prosecutors’ offices to create the appearance that high-profile or politically important cases are being resolved quickly.
The investigative methods used in most prosecutors’ offices and the rules of Mexico’s criminal justice system can also play a role in facilitating these practices. Investigators in Mexico rarely record witness interviews. Instead, they usually write a written statement based on an informal interview and ask the witness to sign it. In the initial stages of the criminal process, these written statements, which can contain errors and inaccuracies, are often sufficient to open a criminal case and obtain the pre-trial detention of the defendant, even before formal criminal charges have been presented, leading many people to spend months or even years in pre-trial detention.
Poor Incentives: Focus on Pre-Trial Detention and Numerical Targets
At an institutional level, opening cases based on weak, coerced, or fabricated evidence can be an easy way for authorities to create the appearance they are resolving cases that are politically sensitive or that are drawing negative media attention for the government or the prosecutor’s office. As one lawyer from a state victims’ commission explained:
In our state, the victims’ collectives get a lot of media attention. They hold protests and create problems for the prosecutor’s office. In those cases, the prosecutors want to move quickly instead of doing the investigation well. They end up fabricating most of the evidence because of social pressure.
In addition, many prosecutors, victims’ advocates, and defense attorneys interviewed for this report said they believe investigative police officers and prosecutors frequently alter or fabricate testimonies in order to improve their performance metrics. As one prosecutor explained:
The prosecutor’s office in my state is focused on having something quantitative. It’s all about meeting goals. That means there are many investigations that are deficient or just made up… It means fabricating witness statements, modifying witness statements, fabricating records from the investigation, fabricating evidence.
In the states where Human Rights Watch conducted interviews, investigative police officers and prosecutors said that their teams’ performance is usually evaluated based on whether they meet set numerical targets each month. These targets are set depending on the stage of the investigation or prosecution for which each team or unit is primarily responsible.
For example, investigative police officers are typically focused on the initial stages of the investigation, collecting evidence and interviews and identifying suspects. The investigative police officers interviewed for this report said their units are usually given a target number of cases to “conclude” each month. A case is considered “concluded,” they said, when a suspect has been identified and prosecutors have been provided with sufficient evidence to request that a judge issue a citation or an arrest warrant.
Prosecutors said their performance is typically measured by the number of cases that are “judicialized,” meaning that a request for an arrest warrant or citation has been filed before a judge or a suspect has been arrested.
Some prosecutors, investigators, and victims’ advocates argued that, by evaluating their performance based only on the initial stages of the criminal proceedings, rather than outcomes of cases, prosecutors’ offices create an incentive for investigators to build cases based on fabricated testimonies and for prosecutors to open criminal proceedings based on limited evidence. As one prosecutor from a unit that investigates intentional homicide cases explained:
In our homicide unit, we have the goal to judicialize a certain number cases each month. So, the investigative police and the prosecutors in the investigative unit just make things up so they can say they have enough cases ready. Each prosecutor is responsible for judicializing at least one case per month. There are some who do two or three in a month. If you do more, even if you don’t have the right evidence, it looks like your performance is better. They don’t care if the case never makes it to trial or gets dismissed later on.
Once a judge has issued a vinculación a proceso, the case enters the “complementary investigation” phase, during which prosecutors are given additional time—up to six months—to attempt to obtain additional evidence and decide whether they wish to present formal criminal charges or request that the case be dismissed and the defendant released.
However, some prosecutors said that, once a vinculación a proceso has been obtained, and investigative police consider a case to be “concluded,” it can often be difficult to get them to comply with requests to obtain additional evidence that would be necessary to obtain a guilty verdict if the case were to proceed to trial.
As one prosecutor, from his state’s homicide litigation team, said:
As far as the investigative police are concerned, once there is an arrest warrant, they are done. They don’t want to hear about the case anymore. When we pick it up, and we see things are missing, we send requests for them to conduct further investigations or conduct additional interviews. But they ignore us. It’s a low priority, because for them, those cases already count as “concluded.”
Mexico’s abusive pre-trial detention rules compound these poor incentives. The country’s constitution and national code of criminal procedure require judges to order pre-trial detention once they have issued a vinculación a proceso for anyone under investigation for over a dozen categories of crime, including intentional homicide, regardless of the circumstances of the case. This means it can be relatively easy for prosecutors to quickly obtain the pre-trial detention of a suspect, based on limited evidence, in order to create the appearance that high-profile crimes are being addressed, without actually taking any of the necessary steps to conduct an effective and impartial investigation that can lead to a conviction.
As the representative of the Office of the United Nations High Commissioner for Human Rights (OHCHR) in Mexico said, in a November 2018 letter to Mexican legislators in which he urged them not to approve an expansion of automatic pre-trial detention:
Since automatic pre-trial detention is a de facto form of anticipated punishment, the country’s prosecutors have an easy incentive to base the apparent effectiveness of the justice system on this anticipation of punishment, instead of investing resources in professional and efficient criminal investigations with a view to proving criminal responsibility in court. With this practice, the development and outcome of the oral trial becomes secondary, since the authorities could be using imprisonment through pre-trial detention as a way of proving, politically and socially, the correct functioning of the justice system.
Once a person has been detained, prosecutors and defense attorneys said, the case may be treated as a lower priority, because, in the eyes of the public, the perpetrator has already been identified and detained. As one judge said:
Everyone forgets about defendants who are in pre-trial detention. There are so many cases where they get a vinculación a proceso and then they don’t bother to present formal criminal charges.
One result of this approach to criminal prosecutions is that many people accused of intentional homicide spend excessive amounts of time in pre-trial detention. The National Code of Criminal Procedure (CNPP) limits the period of complementary investigation to a maximum of six months and both the CNPP and the Mexican Constitution grant all defendants the right to a trial within one year. Additionally, under the Mexican Constitution, no one may be held in pre-trial detention for more than two years. However, many people accused of intentional homicide are detained without sentence for significantly longer. In the most recent survey of incarcerated people, conducted by Mexico’s national statistics agency in 2020 and 2021, 3,359 of the around 67,000 respondents were being held in pre-trial detention on intentional homicide charges. Nearly 40 percent of them said they had been in pre-trial detention for more than the two-year limit established by the Mexican Constitution. A quarter said they had been in pre-trial detention for five years or more.
Under international law, pre-trial detention should only be used in exceptional cases, based on an individualized determination that it is necessary for purposes such as preventing flight, interference with evidence, or the recurrence of crime. The United Nations Human Rights Committee (HRC) has said that automatic and extremely prolonged pre-trial detention can violate the right to a prompt trial and jeopardize the presumption of innocence. The Inter-American Court of Human Rights ruled in 2022 and 2023 that Mexico’s use of automatic pre-trial detention violates international human rights standards and ordered Mexico to reform its laws and constitution to eliminate the practice.
The Mexican government has defended its use of automatic pre-trial detention, publicly refused to comply with the ruling of the Inter-American Court and amended the constitution to expand its use. In August 2022, then-Interior Secretary Adán Augusto López said that eliminating automatic pre-trial detention would “put an end to the entire security strategy” of the federal government.
Overreliance on Witness Testimony
Prosecutors in Mexico rely heavily, sometimes exclusively, on witness testimony to investigate and prosecute intentional homicide cases. Nearly every prosecutor, judge, or other justice operator interviewed for this report agreed that most of the convictions for homicide or femicide obtained in Mexican courts are based primarily on witness testimony. As one judge explained:
In a murder case, you can have many types of evidence. But what is most important? It’s witnesses! You need a witness who can say “I saw that person shoot the victim.” In my 17 years as a judge, I’ve presided over only a handful of cases based on scientific evidence. If the prosecutors conduct an exhaustive investigation, and they present lots of scientific evidence like fingerprints or ballistics analysis, then witness testimony falls to the background. But that rarely happens. Usually the investigators say “We have a witness who gave a credible story. That’s enough. Next case.”
In the most recent survey of incarcerated people, conducted in 2020 and 2021 nearly 70 percent of respondents who had been imprisoned on intentional homicide charges said the case against them had been based primarily or exclusively on witness testimony. Only 10 percent said prosecutors had presented any scientific evidence against them, like fingerprint or DNA analysis. And only 12 percent said prosecutors had presented documentary evidence, like photographs or phone records.
Some of the legal advisors from state victims’ commissions interviewed for this report expressed frustration that even in cases where there is relevant scientific, physical, or documentary evidence available, prosecutors are often focused only on obtaining witness testimony, either because they believe that proving a case based on other types of evidence would be too difficult or because they believe that judges are only interested in witness testimony. As one legal advisor explained:
If someone can pick the defendant out of a line up, that is enough for most judges to convict. So, prosecutors don’t want to bother with other kinds of evidence. I recently worked on a femicide case where we collected all kinds of evidence: proof that someone had used the victim’s debit card after she was killed, DNA samples from under the victim’s fingernails, friends who said there was a history of abuse. I have a degree in criminology. I know how this works. But when we gave it to the prosecutor, he just said to me, “Damned, useless evidence. Where is the witness?”
Unexecuted Arrest Warrants
One reason why many intentional homicide prosecutions never advance beyond the initial stages is that, sometimes, investigative police do not execute the arrest warrants prosecutors have obtained, meaning the person under investigation never appears in court and the initial hearing never takes place. According to information Human Rights Watch obtained through transparency requests, from 2016 through 2023, judges in 20 states (the other 12 did not provide complete information) issued nearly 20,500 arrest warrants for intentional homicide. During the same period, prosecutors’ offices in those states executed around 11,500 arrest warrants for intentional homicide, just over half of the number issued by judges, although Human Rights Watch was unable to confirm whether the appearance of the accused person before a judge was eventually secured in any of these cases.
Many of the legal advisors from state victims’ commissions interviewed for this report said that once an arrest warrant is issued, prosecutors often do not take action to execute the warrant unless victims’ families push them to do so and that they sometimes rely on families to assist in locating the suspect or otherwise facilitating the arrest. As one legal advisor said:
It can be so frustrating for victims’ families. They tell us “I see him leaving his house every morning to go to work as if nothing happened. I already gave the prosecutors so much information. I told them where they could find him. Why don’t they do anything?”
As another legal advisor explained, investigative police don’t necessarily act to execute outstanding arrest warrants in the absence of external pressure from victims’ families:
I represented the family of a woman who was killed by her boyfriend. The prosecutors got an arrest warrant very quickly. But then nothing happened for months. I would ask my friend at the investigative police what was going on. He would tell me “You think this is our only case? We’re very busy.” Finally, we filed a complaint before the judge and the family got the local news to run a story about the case. Once that happened, it took less than a week for them to arrest the guy.
Weak “Complementary Investigations”
Some of the prosecutors, judges, defense attorneys, and victims’ advisors interviewed for this report said a common shortcoming they see in intentional homicide cases is that prosecutors often request arrest warrants and vinculaciones a proceso based on limited evidence, evidence with factual inaccuracies, or written testimonies from witnesses who would be unwilling to appear in court if the case were to proceed to trial, and then conduct very little additional investigation during the complementary investigation phase. The result, as one judge explained, is that “usually, the evidence prosecutors present in the initial hearing is the same evidence they use at trial. It’s really very rare that they conduct further investigation once the person is detained.”
In many of the cases that legal advisors from state victims’ commissions described in their interviews with Human Rights Watch, additional, relevant pieces of evidence or witness testimonies were often readily available or had already been provided to prosecutors by victims’ families. But, they said, prosecutors often wrongly told victims’ families that the additional evidence would not be necessary to obtain a conviction or else insisted it would be too costly and time-consuming to have additional physical evidence analyzed by forensic technicians or to send investigative police officers to conduct interviews with additional witnesses. This practice can lead to detention of people on the basis of weak evidence and can result in the dismissal of the charges or a not-guilty verdict at trial.
A legal advisor from a state victims’ commission described one such case, for example:
I worked on an intentional homicide case recently where the key piece of evidence was that the defendant had been found with blood on his clothes and shoes. To open the case and get a vinculación a proceso, the prosecutors just showed the judge pictures of the defendant’s bloody shoes. The idea was that, during complementary investigation, they would get the blood tested to prove it belonged to the victim, so we could show the test results at trial. But they never did that. After the vinculación a proceso, the case got passed from the investigations area to the litigation area. And the litigators didn’t read the case file for months. By the time they did, it was too late, they were about to go to trial. So, we went to trial with a case based on a picture of a shoe. Obviously, we lost.
Another challenge that prosecutors, judges, and legal advisors from state victims’ commissions mentioned is that, even when other evidence is available, prosecutors often base cases primarily or exclusively on the testimony of just one witness, often the victim (in the case of an attempted homicide) or a member of the victim’s family. As discussed previously in this report, many people who sign written witness statements at the beginning of a criminal investigation are unwilling to appear in court if the case goes to trial, often due to fear of retaliation. In these cases, lawyers from state victims’ commissions said that prosecutors sometimes fail to take steps to obtain additional evidence and instead focus on pressuring the sole witness to testify. If the witness does not agree to do so, prosecutors may simply allow the case to be dismissed or proceed to trial with limited evidence.
One legal advisor from a state victims’ commission mentioned two examples of this problem in cases she had worked on:
I recently represented the parents of a teenager who had survived an attempted homicide. The case went to trial with just one witness: the victim. The parents told me there were neighbors who had seen what happened and were willing to testify, but the prosecutors never tried to speak to them. In the end, the young man was too afraid to testify in court. His mother told me he was getting threats. With no witnesses, the case ended in a not-guilty verdict.
Now, I’m working on another case. It’s a man who was killed at a bus station. There were cameras there and lots of witnesses. But the prosecutors haven’t tried to get the camera footage or spoken to anyone who works at the bus station. They just want the victim’s girlfriend to testify. She told me she is afraid to speak in court. I’m trying to convince her. But if she doesn’t agree to testify, I have a feeling this case will never go to trial.
Prosecutors and legal advisors from state victims’ commissions also said they have seen prosecutors initiate criminal cases based on evidence or testimonies that contain apparently unintentional factual inaccuracies, such as incorrect dates or names.
Encouraging Witnesses to Give False or Inaccurate Testimony
Prosecutors and investigative police officers also sometimes encourage victims, their family members, or other witnesses to provide false testimony aimed at incriminating the person or people whom authorities believe perpetrated the crime. Nearly everyone interviewed for this report, including victims’ advocates, prosecutors, defense attorneys, and investigative police officers said this practice is a common method prosecutors use to build criminal cases.
One way that investigative police alter witnesses’ statements, prosecutors said, is by encouraging them to add or change key details to coincide with the description of the person authorities believe to be the perpetrator. For example, when conducting interviews with lay witnesses —those who witnessed events near the scene of the crime—investigators may provide them with the full name and description of the person they believe is responsible and encourage them to include the suspect’s name and description in their statement, saying they knew and recognized that person at the crime scene. Some prosecutors interviewed for this report said they have received case files in which these types of details have been added into witness statements. One prosecutor gave an example:
When I receive a case file, the first thing I do is review all the evidence and talk to the witnesses who signed written statements. In one case recently, there was a video of the perpetrator. So, I watched it, and the person in the video didn’t look like the defendant at all. I spoke to the two witnesses who both had signed statements naming the defendant and saying they had seen him at the scene of the crime. They both said to me “Oh, I don’t know who that is. But the officer who interviewed me told me that’s who did it. He said I should name him in my statement, so I did.”
Some of the investigative police officers interviewed for this report said they sometimes “help” witnesses fill in other details in their written statements, by showing them photos or videos from the crime scene and then including details from the photos or videos as if the witness had seen them firsthand. One explained how he typically conducts an interview with a witness:
I’ll say: ‘What color hair did he have? What was he wearing?’ If the witness can’t remember, I’ll show them a photo or a video and say: ‘Can you see here he had a red shirt on?’ Then I’ll add that detail as I’m writing down their statement and ask them to sign it.
Lawyers from state victims’ commissions described cases in which investigators had initially conducted interviews “informally,” without keeping official records of them, so that, once they have identified a suspect, they can add or remove details from the final version of the statement that will be entered as evidence in the investigative file to ensure the description coincides with the identity of the person they believe is guilty.
When we ask for the case file so we can review it with the victim’s family, the prosecutors tell us they can’t give us a copy yet because the investigation is still “informal.” They’ll say: “If you want me to give you a copy, then I’ll need to formalize everything. Then we won’t be able to change any of the details later.”
In other cases, prosecutors or investigative police officers encourage victims’ family members to provide false testimony, often insisting that doing so would be the easiest way, or the only way, to achieve a conviction against the perpetrator in court, lawyers from victims’ commissions said. The types of testimony family members are encouraged to provide vary. In some cases, family members were told to say they had been present at the time of the murder and could identify the perpetrator, as one lawyer from a victims’ commission explained:
Prosecutors call us up and say, “We found fingerprints at the crime scene, and we’ve arrested the person they belong to. I need you to bring in the victim’s next-of-kin to identify the suspect in a lineup so we can press charges.” When I speak to the victim’s family, they say, “But we weren’t there? How can we identify a person we’ve never seen?” The prosecutor tells them “Listen, it doesn’t matter. We know this is the guy. We just need you to sign a statement saying you recognize him.”
In other cases, such as the following example, also described by a lawyer from a victims’ commission, prosecutors encourage victims’ family members to provide false testimony saying they had been threatened by the alleged perpetrator, in order to make the criminal case stronger:
I recently represented the father of a man who had been shot in the street outside of his workplace. When we met the prosecutor in charge of the case, he told us they had already detained the person responsible for the murder. He said if we wanted to make sure he would be convicted, the father should sign a false statement saying he had received threatening phone calls from the man, since that would demonstrate his link to the case. The father refused. He said he wanted a real investigation. The prosecutor got angry and said, “You already know what happened. Why should we investigate?”
Additionally, lawyers from victims’ commissions said that, in some of their cases, prosecutors have told victims’ families that the person responsible for their relative’s murder is either dead or already in jail for another crime and asked them to provide false testimony incriminating a different person. In one case, for example:
I represented a man whose son had been murdered. He had already given prosecutors the name of the person he believed had killed his son. The prosecutors asked him to come in and identify someone in a lineup. When he got there, they said: “Listen, the man whose name you gave us is already in jail for another crime. But we want you to identify someone else. He’s also a bad guy. If you say he killed your son, you can help us put him in jail too.”
Prosecutors and legal advisors from state victims’ commissions said that in cases in which officials have altered or fabricated testimony from witnesses or family members, they are often reluctant or unwilling to testify to the same version of events in court. When witnesses and victims’ family members do agree to testify, they sometimes inadvertently reveal falsehoods or contradictions between their oral testimony and their initial written statements. Many prosecutors, victims’ advocates, and defense attorneys recounted stories of hearings in which, while on the stand, witnesses contradicted themselves and, eventually, when questioned, admitted that authorities had pressured them to alter or change their written testimony. As one prosecutor said:
For us, as litigators, when our colleagues fabricate testimonies and evidence, it means that, when we get to trial, there’s a moment when the witness is on the stand and we ask them about some detail from their written statement and they say “Actually, I never said that.” Or in other cases, the witnesses will repeat their original testimony, but it doesn’t actually line up with the facts.
Statements Obtained through Threats, Abuses, and Torture
Prosecutors and investigative police sometimes attempt to “resolve” murder investigations by threatening, mistreating, or torturing people in their custody, or allowing other authorities to do so on their behalf, in order to coerce them into pleading guilty to crimes, incriminating another person, or otherwise altering their testimony to corroborate a false version of events. Mexican authorities’ use of torture to attempt to resolve criminal cases has been extensively documented by many human rights organizations, including Human Rights Watch, experts from the United Nations and the Inter-American Human Rights Commission, and officials from Mexico’s own state and federal human rights authorities.
It is difficult to know how many of the intentional homicide cases prosecuted every year are based on statements obtained through torture. One important source of information is the national statistics agency’s regular survey of incarcerated people, most recently conducted in 2020 and 2021. Authorities interviewed more than 67,000 people in 203 prisons, including around 5,200 who had been detained on intentional homicide charges since the transition to the adversarial justice system was completed in 2016. The results confirmed that torture is still widely used to attempt to “resolve” intentional homicide investigations.
Among the national statistics agency’s interviewees who had been detained for intentional homicide since 2016, around half reported they had been beaten, asphyxiated, waterboarded, or burned, given electric shocks, been sexually assaulted, or been subject to some other form of physical abuse either while in the custody of the authorities who initially detained them, or later while being held at their state prosecutor’s office. Of those who were interrogated while in the custody of prosecutors, around 40 percent said they had been beaten or mistreated in order to coerce them into either signing a confession, incriminating another person, or agreeing to accept a “false version of events.”
Of those who made a formal witness statement while detained, just over 35 percent said they were allowed to read the statement before signing it, and just over one-third said prosecutors or investigators pressured them to alter the facts in their statement and include false information that would incriminate themselves or someone else. Of those who confessed to murder, around 28 percent said they only did so because their interrogators had threatened or beaten them.
One of the public defenders interviewed for this report provided a description of the most common types of torture and abuses her clients have suffered while being interrogated by authorities from her state’s prosecutor’s office. Many of her clients suffer abuses, she said, but they are most frequent among those who have been accused of intentional homicide, kidnapping, or drug-related crimes.
Typically, after a person is first detained by the investigative police, they bring them in for questioning. Usually, they tie a plastic bag over the person’s head to make it difficult to breathe. They also put them in handcuffs, so that they can’t take off the plastic bag. Sometimes, they put some hot sauce inside the bag. That makes it even more painful. The person is breathing in the hot sauce. It’s burning their eyes. Then they start kicking and beating the person until they get what they want: a promise to plead guilty, an agreement to testify against someone, or information they could use to arrest other people, like the names of people who buy or sell drugs.
Ineffective Legal Reforms
In recent years, Mexico has implemented a number of constitutional, legal, and procedural reforms, some of which were aimed at strengthening due process guarantees and eliminating the perverse incentives for prosecutors and other justice operators to build criminal cases based on coerced or fabricated evidence. The most notable among these was the justice system reform, passed in 2008 and implemented between June 2008 and June 2016, to transition from an inquisitorial model—in which most evidence is presented in writing—to an adversarial system where the prosecution and defense present competing arguments in oral trials. The reform included measures that require all witnesses to appear in court and present their testimony orally and that prohibit the use of confessions made without a defense attorney present or statements obtained through torture. Also important was the passage, in 2017, of the General Law to Prevent, Sanction, and Investigate Torture, which strengthened the prohibition on using evidence obtained through torture and required all state prosecutors’ offices to create specialized anti-torture units.
These reforms have been largely ineffective at stopping abuses or at encouraging investigators and prosecutors to conduct real, effective criminal investigations. There are a few key reasons why. First, most investigators continue to use a process for recording interviews with witnesses, victims, and the accused that often leads to errors or facilitates the use of coerced or fabricated testimony. Second, judges often face pressure to issue vinculaciones a proceso or convictions even when there are weaknesses or inconsistencies in the cases presented by prosecutors. And third, public defenders and prosecutors often pressure defendants into agreeing to accept a guilty plea without going to trial, which makes it much easier for fabricated evidence or coerced testimonies to go unexamined.
Interview Method
One of the factors that contributes to the use of inaccurate, altered, or fabricated witness testimony in intentional homicide cases in Mexico is the method investigators commonly use to conduct and record their interviews with victims, witnesses, and those accused of crimes. Typically, investigators said, they conduct interviews informally, without keeping any audio, video, or written record of the questions asked, or the answers received. Once finished, they write a statement on behalf of the witness, in the form of an uninterrupted, first-person account of the events, and ask the witness to sign it. In some cases, investigators and prosecutors told us, they “help witnesses fill in details” by asking leading questions, showing photos or videos from the crime, or providing information like full names, dates, and locations. While the resulting text contains some useful information, it is by no means a full or accurate account of what was asked or what was answered.
In 2016, the Interdisciplinary Group of Independent Experts (GIEI) sent by the Inter-American Commission on Human Rights (IACHR) to examine authorities’ investigation of the Ayotzinapa mass enforced disappearance case said the “serious deficiencies” in Mexican authorities’ interview methods were one of the key problems limiting the effectiveness of investigations into human rights violations in Mexico. As the GIEI explained:
A witness statement should have, textually, not just all the questions asked, but also all the answers given, including quotation marks. Indicating the questions and answers is fundamental to know what was asked, how it was asked, and to know what was answered and how it was answered. It is essential to know if all concerns regarding a witness were asked, and if they were formulated appropriately, that is, avoiding questions that are insinuating, those that suggest an answer, or are poorly formulated, and to know, exactly, each one of the answers, since, often, the person might simply respond ‘no’ or ‘I don’t know.
The GIEI added that, when they asked the prosecutors on the Ayotzinapa case to begin transcribing the full text of their interviews in this way, they discovered that:
In many witness statements, the questions contained part of the answers, meaning that, ultimately, the person who was providing the information, including information that had never been provided at any point by the witness, was the person asking the questions, not the witness.
Allowing investigators to draft witness statements without recording the context in which the information was obtained makes it incredibly easy for investigators to alter or fabricate witness statements. It also makes it much more difficult to determine whether a witness statement was obtained following an interview that involved threats, abuse, or torture.
Some of the prosecutors interviewed for this report said that when they take over a case that was opened by someone else, they are sometimes unsure of the veracity of the information in witness statements and feel the need to speak with witnesses to confirm the information in their statement.
In addition to the issue of intentionally false or coerced information, legal advisors, both private and from state victims’ commissions, said this practice can often lead to unintentional errors, such as incorrect dates, names, and locations, or to key information being left out of the statement, particularly when the person conducting the interview has no prior knowledge of the case.
While international law does not require that witness interviews be conducted in a specific manner, the Minnesota Protocol on the Investigation of Potentially Unlawful Death recommends that “[w]here feasible and appropriately secure, investigators should consider recording their interviews by video or audio means.” The Principles on Effective Interviewing for Investigations and Information Gathering (the “Méndez Principles”), developed by a group of experts led by former UN Special Rapporteur on Torture Juan E. Méndez, also recommend that an accurate record of witness interviews be made “preferably with the use of audio-visual technology.”
Pressure on Judges to Issue Rulings Favorable to Prosecutors
Judges in Mexico sometimes face pressure to issue rulings favorable to authorities. In most states, the governor exercises significant influence over the functioning of the justice system, enabling the governor to pressure judges to issue favorable rulings in cases that are politically relevant or that have received significant media attention. In addition, federal government officials often publicly single out judges who fail to issue such rulings and accuse them of being “corrupt” or “favoring criminals.” In some cases, state or federal authorities have even retaliated against judges who fail to issue favorable rulings, by withdrawing protection measures or charging them with crimes.
At a state level, most governors exercise an outsized level of influence over the appointment of the state attorney general and the judges on the state’s highest court, which in turn can allow the governor to exercise significant influence over the selection of the chief justice of that court and the appointment of the members of the governing body of the state judicial system. Following her most recent visit to Mexico in 2010, the UN special rapporteur on the independence of judges and lawyers expressed concern regarding the high level of control that state governors exercise over their state court systems. The rapporteur said:
This link with the executive branch is so strong that, in practice, the [executive branch] also determines who will be appointed chief justice, which can seriously undermine the independence and autonomy of the bodies charged with administering justice at the local level. During her visit, the Special Rapporteur was witness, on at least two occasions, to the existence of an unusually close relationship between a chief justice and the governor of the state in question.
A more recent analysis, published by the organization México Evalúa in 2023, found that the lack of safeguards to protect the independence of state judicial systems in Mexico continues to be a problem. The report, which analyzed legal and institutional frameworks in all 32 states, found that, in many states, the governing body of the judicial system is given extremely broad discretion over many aspects of the functioning of the system, such as decisions about the hiring, promotion, and removal of judges or decisions about which judges hear which cases. In 15 states, for example, there are no formal rules establishing the circumstances under which the governing body may or may not remove a judge from office. In 26 states there are no rules establishing when or how the governing body can decide to reassign a judge to a different court or region. And no states legally require that the governing body of the judicial system establish objective rules regarding how cases are assigned. This can make it easier for senior judicial authorities to pressure judges to issue rulings that are favorable to state prosecutors or to the interests of political leaders and to threaten them with reassignment or sanction if they fail to do so.
Human Rights Watch interviewed one judge for this report who explained how these dynamics often play out in her state:
In my state, when we receive a high-profile case, or one that is politically important, the coordinator for the judges in our region also gives us instructions from the chief justice or the governor. We might get told to dismiss the case, if it’s a political ally, or to indict, or convict, if it’s a high-profile crime, like a murder. When the current governor was elected, we started getting the instruction to order pre-trial detention for everything, even petty theft. If we refuse, there are consequences. They take the case away from you and re-assign it to a judge who will rule the way they want. They’ve threatened to transfer me to the middle of nowhere or revoke my tenure.
I presided over a case a few years ago. It was a very grisly cartel murder. The whole case was based on the testimony of one man. In court, the defense attorney provided video evidence showing both defendants were in other locations at the time of the murder. One was out of state. The other was at work.
I did not find sufficient evidence for a vinculación a proceso and the defendants were released. I got so much criticism. The media accused me of being corrupt. And the chief justice called me to say the governor was furious because I made it look like the justice system is releasing criminals out onto the streets. He made me write a memo to the governor explaining my ruling. Now, when there are “relevant” cases, they don’t assign them to me. They go to other, more obedient judges.
In recent years, judges in other states have publicly made similar allegations.
Under the administration of former president Andrés Manuel López Obrador (2018-2024) federal government officials repeatedly used the president’s daily morning press conference to publicly single out judges who ruled against state and federal prosecutors, accusing them of being “corrupt” and “favoring criminals” without supplying any evidence of wrongdoing. From 2023 to 2024, the government began including a biweekly segment in the daily morning press conference called “Judges Who Favor Criminals.” In some cases, judges have reported facing apparent retaliation, such as the withdrawal of personal security measures, which are granted to judges at risk.
In September 2024, Congress approved a series of constitutional amendments that will significantly change the way that state and federal judges are appointed and disciplined. Under the new rules, federal judges will be popularly elected every nine years from a list of candidates chosen by the Congress, the president, and the Supreme Court.All 32 state legislatures are required to amend their state constitutions to implement a version of this system in their state courts before March 2025, meaning that, starting in mid-2025, all state judges will be elected by popular vote from a list of candidates chosen by state governors, state legislatures, and state Superior Courts. The changes also require the creation of new judicial discipline tribunals, whose members will be chosen by popular vote and who will have broad powers to sanction or remove judges “who commit acts or omissions contrary to the law, the administration of justice, or the principles of objectivity, impartiality, independence, professionalism, or excellence.”
Mexican and international human rights organizations, including Human Rights Watch, and international human rights authorities, such as the IACHR and the UN Special Rapporteur on the Independence of judges and lawyers warned these changes will do little to address the shortcomings in state justice systems and, instead, are likely to further undermine judicial independence.
Pressure on Defendants to Accept Plea Bargains
Another factor facilitating the use of fabricated or coerced evidence and testimonies in intentional homicide cases is prosecutors’ frequent reliance on plea bargains to resolve cases. One of the goals of Mexico’s transition to the adversarial justice system was to make it more difficult for prosecutors to base their cases on altered, fabricated, or coerced evidence, since, under the adversarial system, witnesses must appear in court to give their testimony orally. However, if a defendant agrees to plead guilty in an abbreviated procedure (more commonly known as a plea bargain), prosecutors are able to obtain a guilty verdict without the risk that inconsistencies or contradictions in their case come to light in an oral trial. In 2021, around 40 percent of intentional homicide sentences were obtained through an abbreviated procedure.
Some defense attorneys and judges said they believed that, in their experience, prosecutors often take advantage of the fact that anyone subject to a vinculación a proceso in an intentional homicide case will be placed in pre-trial detention and focus on using the complementary investigation period not to conduct additional investigation, but to attempt to convince people being held in pre-trial detention to agree to an abbreviated procedure. As one public defendant explained:
In my state, the prosecutors’ strategy is to judicialize everything they can and try to get a vinculación a proceso just to get people in pre-trial detention. Once someone is in prison, they are much more willing to agree to a plea bargain. The truth is that most people who get accused of these crimes are poor. They don’t understand how the legal system works, and they can’t afford a private lawyer who can explain it to them. They just want certainty about how long they will be in jail. Waiting for a trial can take years.
Compounding this issue is the fact that public defenders sometimes feel pressured to encourage their clients to accept plea bargains, rather than to vigorously defend them. This is in part due to a severe lack of staff and resources in many states’ public defenders’ offices, which limits the ability of public defenders to invest significant amounts of time in investigating the individual case of each client. But it is also due, in part, to the fact that, in most states, public defenders’ offices are either part of the judicial branch or part of the executive branch, leaving public defenders exposed to the same kinds of pressures as judges. One public defender said that she and her colleagues are often encouraged not to conduct investigations aimed at identifying potentially exculpatory evidence on behalf of their clients in order to avoid creating the perception that the court system is ineffective:
I’ve faced retaliation from within the public defender’s office for defending clients too vigorously. I represented the defendant in a case recently that was a high priority for the government. It was pretty clear to me that a lot of the evidence had been fabricated. But as soon as I started trying to dig deeper, I started to get harassed by the police. Finally, my boss called me and told me I needed to just drop it and let the defendant be found guilty. Most of my colleagues tell me that if the family doesn’t get involved in the case from the beginning, they will almost always recommend that the defendant plead guilty.
According to the most recent survey of incarcerated people, conducted by the national statistics agency in 2021, 40 percent of respondents who had been convicted of intentional homicide in an abbreviated procedure said they had been pressured to plead guilty, and among those respondents, nearly 60 percent said their defense attorney had been the one who pressured them to do so.
One of the most important factors determining the success or failure of a homicide investigation in Mexico is the participation of victims’ family members. Prosecutors in Mexico rely heavily, sometimes almost exclusively, on victims’ family members to obtain information and physical evidence, provide testimony, and to identify possible witnesses. Close family members often have information about a victim’s life, friends, and contacts that can play a key role in helping investigators determine what happened. Additionally, in the weeks and months after a murder, friends, neighbors, or associates of the victim often seek out family members to share relevant information. When family members are unable or unwilling to participate in an investigation, prosecutors may treat the case as a lower priority and fail to follow up in a timely manner. Nearly everyone Human Rights Watch interviewed for this report agreed that it is exceedingly rare for a homicide case to be solved in Mexico without the active participation of the victim’s family. While most homicide victims in Mexico are men, the prosecutors, investigative police officers, and legal advisors interviewed for this report said that the family members who follow up on investigations are usually women.
The important role of family members in investigations is recognized in international human rights standards. The United Nations Human Rights Committee, in General Comment 36 on Article 6 of the International Covenant on Civil and Political Rights (ICCPR), the Right to Life, says that states should “disclose relevant details about the investigation to the victim’s next of kin, allow the next of kin to present new evidence, [and] afford the next of kin legal standing in the investigation.” The committee also said that states must “take the necessary steps to protect witnesses, victims and their relatives… from threats, attacks and any act of retaliation.” The Minnesota Protocol on the Investigation of Potentially Unlawful Deaths also highlights the important role of family members in murder investigations.
Mexican law also recognizes the important role of family members in criminal investigations. The Mexican Constitution, the National Code of Criminal Procedure, and the 2013 General Victims’ Law all grant victims of crime the right to actively participate in every stage of the investigation and prosecution. They have the right to access information from the case file, request that specific investigative acts be conducted, present additional evidence, receive protection measures, and appeal before a judge when they believe prosecutors have improperly handled their case, such as by failing to effectively investigate. When the victim of a crime is deceased or otherwise unable to exercise these rights, Mexican law recognizes their next-of-kin as an “indirect victim” who can act on their behalf.
Despite this broad recognition of the crucial role of victims’ family members, legal advisors from state victims’ commissions and lawyers from human rights organizations said it is often difficult for family members to effectively exercise their right to participate in investigations. Family members are often reluctant to participate in investigations, either because they are distrustful of the justice system or because they fear retaliation by perpetrators. When family members do attempt to participate in investigations, they often face hostility from prosecutors, who sometimes refuse to give them access to information from the case file, delay or refuse to carry out investigative steps they have requested, or blame victims or family members for their deaths. This response can contribute to family members’ reluctance to participate in the investigation or share crucial information with prosecutors, making it less likely the case will be solved and often leading prosecutors to view the case as a lower priority.
As one lawyer from a state victim’s commission said:
In the seven years I’ve been doing this, I mostly see two situations. Sometimes, families are distrustful of prosecutors from the very start. They refuse to participate in the case and prosecutors don’t pursue it because they think the family doesn’t care. Other times, families start off feeling hopeful. They believe prosecutors will solve the case. They give testimony. Bring in evidence. Talk to witnesses. Then, the prosecutor starts to ignore them and mistreat them, and they grow disillusioned. Eventually, they give up. Either way, the result is the same. The case never gets solved.
Overreliance on Family Members to Investigate
Family members can play a crucial role in homicide investigations. However, prosecutors in Mexico frequently put much of the burden on families and their legal advisors to investigate crimes, identify witnesses, and locate evidence, many legal advisors said. Nearly everyone interviewed for this report, including prosecutors, investigative police officers, and legal advisors, agreed that one of the main reasons homicide and femicide cases go unsolved is that, once the initial investigative steps have been taken, such as collecting evidence from the crime scene and identifying the victim’s remains, prosecutors often do not follow up on cases unless the victim’s family is pressuring them to do so. As one legal advisor said:
Usually, when cases don’t move forward, it’s because the victim’s family didn’t take action or didn’t follow up with the prosecutors. I always tell the families I am representing: If you want this case to be solved, you need to do everything yourself. If you wait for the prosecutors to investigate, nothing will happen. The case will never move forward.
In many cases, legal advisors said, family members are initially reluctant to participate in the investigation, either out of fear of retaliation, fear of revictimization, or simply because they are mourning the death of their loved one. They said prosecutors often interpret this reluctance as disinterest, leading them to consider the case a lower priority. As one legal advisor explained:
Usually, when family members come to us, it’s a year or more after the murder. They want to know about the status of the investigation. But when we bring them to talk to the prosecutor, they say “Well, you never came to speak to us, so we never investigated.”
When family members do attempt to participate in the investigation, such as by suggesting possible witnesses to interview, legal advisors said that prosecutors often ask family members and their legal advisors to follow up on these suggestions themselves, claiming they do not have the time or resources to do so without families’ assistance. In one such case, described by a legal advisor:
I’m representing a woman whose daughter had run away and was found dead in a vacant lot, months later. Since the mother hadn’t seen her daughter in months, the prosecutors didn’t have any leads. The mother started investigating on her own. She found a security camera video of her daughter at a convenience store on the other side of the city from a month before she died. We got a copy of the video and gave it to the prosecutors. Then we asked them to send an investigative police officer to question the people who work at the store to see if they knew anything about her. But they still haven’t done it. They said, “Why don’t you do it and let us know what you find?”
Many legal advisors interviewed for this report noted that this overreliance on victims’ families to follow up on investigations can create a significant burden for surviving family members, who are often women. As one legal advisor said:
Following up on cases takes time and money. It can mean finding childcare and missing a day of work. And it can be dangerous when family members feel obligated to search for evidence or try to identify possible witnesses on their own.
Under Mexican and international law, prosecutors have an obligation to investigate homicides, regardless of whether the victim’s family has chosen to actively participate in the investigation. Mexico’s National Code of Criminal Procedure (CNPP) establishes that:
When prosecutors have knowledge of the existence of an event that the law considers a crime, they will direct a criminal investigation, which cannot be suspended, interrupted, or ceased, except in cases authorized by law.
The investigation should be conducted immediately, efficiently, exhaustively, professionally, and impartially, free from stereotypes and discrimination, aimed at exploring all possible lines of investigation supported by facts to solve the event the law considers a crime, as well as the identification of the person who committed it or participated in its commission.
This obligation also exists under international law. The UN Human Rights Committee has established, in General Comments 31 and 36, that, if authorities are aware of any potentially unlawful deprivation of the right to life, they have a duty to conduct an independent, impartial, prompt, thorough, effective, and credible investigation and, where appropriate, to prosecute those responsible. The Inter-American Court of Human Rights has repeatedly ruled that authorities have a legal obligation to investigate crimes:
[…] in a serious manner and not as a mere formality preordained to be ineffective. An investigation must have an objective and be assumed by the State as its own legal duty, not as a step taken by private interests that depends upon the initiative of the victim or his family or upon their offer of proof, without an effective search for the truth by the Government.
Blaming the Victim
Prosecutors in Mexico frequently assume that homicide and femicide victims were members of criminal groups or were engaged in other types of criminal or high-risk activities, many legal advisors and representatives of human rights organizations that represent victims of crime interviewed for this report said. They also often scold family members, saying they are to blame for allowing victims to do things like use or sell drugs, stay in abusive relationships, or go to parties late at night.
Nearly every legal advisor, private lawyer, and lawyer from a human rights group representing victims of crime interviewed for this report described multiple cases in which prosecutors had attempted to blame victims in order to justify their failure to take basic investigative steps. As one legal advisor said:
I recently represented the family of a man who had been murdered while working at his job at an auto body shop. The authorities believed the shop belonged to a local criminal group and that many of the people who worked there were involved in criminal activity. One day, someone drove by the shop, shot the man, and drove away. When we met with the prosecutor to ask why there was no progress in the investigation, he looked at the victim’s parents and said to them: “You already know what your son was involved in, so why are you asking us to investigate?”
In another case, also described by a legal advisor, prosecutors displayed a similar attitude:
In one femicide case I worked on recently, a young woman’s body was found beaten up in a motel. She had gone to a party the night before and her family thinks she went to the motel with a man she met at the party. Her mother also told us she had previously been in an abusive relationship. There were multiple leads. When I asked the prosecutor why the case wasn’t advancing, he told me, “You should tell the mother this is her fault. She knew her daughter went out to parties and went to motels. She knew her boyfriend hit her. Why should we investigate?”
The Inter-American Court of Human Rights referred specifically to the problem of gender stereotyping in cases of femicide in Mexico in its 2009 decision in the González et al. (“Cotton Field”) case, regarding authorities’ failure to effectively investigate a pattern of disappearances of women in Ciudad Juárez. The Court stated:
[T]he comments made by officials that the victims had gone off with a boyfriend or that they led a disreputable life, and the use of questions about the sexual preference of the victims constitute stereotyping. In addition, both the attitude and statements of the officials reveal that, at the very least, they were indifferent towards the next of kin of the victims and their complaints.
The court also found that:
The creation and use of stereotypes becomes one of the causes and consequences of gender-based violence against women.
Many of the legal advisors from state victims’ commissions interviewed for this report said that when they speak with victims’ family members, they often discover that they have not shared key details about the victim’s life with prosecutors, usually out of fear of being revictimized. As one legal advisor said:
We often find that victims and their families hide information from prosecutors. That information comes out when we are talking with them, but it’s information prosecutors don’t have. They usually do it because they’re afraid of being revictimized or they think it’s their own fault for letting their daughter go to a party or something.
In other cases, they said, family members choose not to participate in the investigation from the beginning because they do not want to reveal to prosecutors that their deceased relatives were involved in crime or other high-risk activities. In another example, also described by a legal advisor:
I had a case earlier this year. A woman came in to ask for help covering funeral costs for her husband and two of her sons. The son was murdered and then, a month later, the husband and the other son were also murdered. At first, she told me she didn’t want to pursue an investigation, but didn’t want to explain why. But eventually she revealed that her husband had been involved in robbery and her sons had used drugs. She assumed that, once prosecutors realized they were involved in criminal activity, they wouldn’t pursue the investigation anyway.
Although prosecutors have a legal obligation to investigate potentially unlawful deaths, regardless of a victim’s history, some legal advisors said that in their states it was common for prosecutors to dismiss homicide cases as unimportant or not worth investigating when it appeared they were related to organized crime.For example, a legal advisor described two such cases:
The police found the body of a man who had been shot in a house that we knew was used to sell drugs. The prosecutor told me ‘This is a win-win. One less criminal on the street.’ In another case, they found people who had been shot and killed at a different location, also known for drugs. The prosecutor said to me ‘Don’t worry about it. This is just drug dealers settling scores.’
The same legal advisor said that:
In our city, the prosecutors have a map of all the cartel territories. They know which group controls each neighborhood. So, they’ll say, ‘Those guys were killed because they crossed the line into that other gang’s territory. As long as they are just killing each other, we won’t get involved.’
The failure to investigate such cases not only contributes to impunity in individual homicide cases, it also creates a pattern in which murders that are possibly linked to organized crime are less likely to be solved. This makes it harder to dismantle criminal groups responsible for violence.
Fear of Retaliation and Ineffective Protection
One of the main reasons many victims and their family members do not actively participate in investigations is out of fear of facing physical retaliation by perpetrators or by their friends or associates, particularly in cases related to organized crime. Most of the staff of state victims’ commissions interviewed for this report said that, in the majority of homicide cases, family members approach them seeking help with covering medical or funeral costs, but do not want to speak directly with investigative police or prosecutors or collaborate with the investigation out of fear of retaliation.
Nearly every legal advisor interviewed for this report described multiple cases in which family members told them they did not want to participate in the investigation because they had received threats from the alleged perpetrators. A legal advisor described one such case:
Just the other day, I accompanied a woman to the morgue to identify the body of her relative who had been killed. I told her it would be helpful if she could speak to the prosecutors, to make a statement and give them any information she might have. She told me she had already received Whatsapp messages from someone saying they were a member of the cartel that committed the killing. The messages had photos and other personal information about her. They said that if she helped with the investigation there would be consequences. She said, “just give me the body, I don’t want to know anything else about the case.”
In many other cases, described by legal advisors, prosecutors, and investigative police officers, victims’ families had initially participated in the investigation, but changed their minds after being threatened or attacked.
As is the case with witnesses, victims of crime and their family members have the right to request and receive protection from the government. Prosecutors’ offices are obligated to provide these measures when they are necessary to ensure victims can participate in investigations and prosecutions. Prosecutors grant protection measures to victims much more frequently than they do for witnesses. In 2022, for example, they granted protection measures to around 608,000 victims of crime, compared to just over 1,100 witnesses. However, as is the case with witnesses, these protection measures are often ineffective. The most commonly granted protection measures in 2022 were a restraining order, prohibiting the accused person from communicating with a victim, a one-off request for police to respond to a call for assistance at a victim’s home, or a request for police surveillance of the victim’s home. In practical terms, prosecutors explained, this usually means that prosecutors sent a letter to the state or municipal police asking for a police officer to visit a victim’s home once or twice per day or provide a phone number the victim can call if they need help.
In some cases, prosecutors, legal advisors, and representatives of human rights organizations said, police do not always consistently comply with these requests. But even when they do, they said, many victims and their family members still feel unprotected and often decide it is too risky to continue collaborating with authorities in the investigation.
As one prosecutor said:
It can be really frustrating because we go through the whole process to get protection measures granted and, in the end, it just means the police give the victim a phone number to call or they say, “we’ll send someone to drive by your house every once and a while.” People end up calling us directly and saying “This isn’t helping. I don’t feel safe. I’m not going to participate anymore.” Or they go on social media and start complaining about how the prosecutor’s office let them down.
Limited Access to Legal Advisors
Legal advisors play an important role in helping victims’ families participate in investigations and navigate Mexico’s complicated and bureaucratic criminal justice system. They can help victims’ families obtain access to case files, review the information in them to ensure it is correct, and file the legal documents necessary to request that authorities conduct additional investigative steps, such as interviewing relevant witnesses or inspecting additional locations related to the crime.
Under Mexican law, victims of crime and their family members have the right to appoint an independent legal advisor to help them assert their interests, although they are not required to do so. When families cannot afford to appoint a private legal advisor, they have the right to request the assistance of a free legal advisor provided by their state government.
Since 2013, all states have been legally required to establish a state victims’ commission or similar state-level entity responsible for helping victims and their family members to obtain free financial, legal, medical, and psychological assistance, including by providing free legal advisors. Human Rights Watch requested information from each state regarding the year its victims’ commission began operating, the number of legal advisors it employs, and the number of cases those advisors attended in 2023. We found that in many states, the victims’ commission began operating much later than 2013 and, in many cases, only has the staff and resources necessary to assist a small fraction of victims.
|
Cases Attended per Legal Advisor at State Victims’ Commissions 2023 |
||
|
State |
Number of Legal Advisors |
Cases Attended per Legal Advisor (all crimes) |
|
Aguascalientes |
33 |
290 |
|
Baja California |
21 |
1,199 |
|
Baja California Sur |
34 |
172 |
|
Campeche |
14 |
1,251 |
|
Coahuila |
19 |
237 |
|
Colima |
24 |
382 |
|
Chiapas |
2 |
26 |
|
Chihuahua |
61 |
298 |
|
Mexico City |
24 |
283 |
|
Durango |
No response |
|
|
Guanajuato |
32 |
289 |
|
Guerrero |
30 |
278 |
|
Hidalgo |
2 |
No response |
|
Jalisco |
63 |
83 |
|
Mexico State |
No response |
|
|
Michoacán |
50 |
206 |
|
Morelos |
0 (Legal area created in 2024) |
n/a |
|
Nayarit |
5 |
936 |
|
Nuevo León |
56 |
131 |
|
Oaxaca |
No response |
|
|
Puebla |
19 |
324 |
|
Querétaro |
42 |
539 |
|
Quintana Roo |
52 |
71 |
|
San Luis Potosí |
40 |
205 |
|
Sinaloa |
15 |
63 |
|
Sonora |
3 |
160 |
|
Tabasco |
1 |
0 |
|
Tamaulipas |
29 |
No response |
|
Tlaxcala |
44 |
240 |
|
Veracruz |
59 |
211 |
|
Yucatán |
18 |
363 |
|
Zacatecas |
25 |
72 |
|
Source: Public information requests filed by Human Rights Watch. See Appendix I for a complete list of information request numbers. |
||
Many of the legal advisors from state victims’ commissions interviewed for this report said that a lack of staff and resources limits their ability to take on a greater number of cases. Many also said they believe that many people still do not understand the role of victims’ commissions and legal advisors in criminal investigations and, as a result, do not proactively seek a legal advisor when an investigation is first opened. Usually, they said, victims seek legal assistance months or years after an investigation has been opened, when they become frustrated by the lack of progress or because prosecutors have stopped providing them with information on the status of the case.
Additionally, many legal advisors told Human Rights Watch that prosecutors often do not initially refer cases to the victim’s commission or wait to do so until a suspect has been identified and legal action has been initiated. Mexican law requires prosecutors to notify victims and their families of their right to appoint a legal advisor and to obtain other types of assistance from their state victims’ commission although prosecutors are not required to forward cases to victims’ commissions and victims may waive their right to a legal advisor or agree to accept legal representation from the prosecutor’s office.
The homicide and femicide prosecutors Human Rights Watch interviewed for this report said that, as a matter of course, they always make victims’ families aware of their right to appoint a legal advisor and that they always refer them to state victims’ commissions for assistance. However, when Human Rights Watch requested data on the number of homicide cases prosecutors had referred to state victims’ commissions in 2022, we found that in the 23 states that provided data, prosecutors had referred just a small portion of cases, and, in some states, they referred no cases at all (see chart below).
|
State |
Intentional Homicide Cases 2022 |
Intentional Homicide Cases Referred to Victims’ Commissions 2022 |
Cases referred as percentage |
|
Aguascalientes |
69 |
0 |
0% |
|
Baja California |
2,956 |
278 |
9% |
|
Coahuila |
143 |
14 |
10% |
|
Colima |
735 |
3 |
0% |
|
Chiapas |
441 |
2 |
0% |
|
Chihuahua |
1,801 |
1,004 |
56% |
|
Mexico City |
970 |
30 |
3% |
|
Durango |
111 |
5 |
5% |
|
Guanajuato |
2,632 |
49 |
2% |
|
Guerrero |
1,137 |
302 |
27% |
|
Hidalgo |
307 |
0 |
0% |
|
Morelos |
1,589 |
397 |
25% |
|
Nuevo León |
1,328 |
323 |
24% |
|
Puebla |
897 |
30 |
3% |
|
Querétaro |
264 |
99 |
38% |
|
Quintana Roo |
562 |
92 |
16% |
|
Sinaloa |
512 |
310 |
61% |
|
Sonora |
1,636 |
0 |
0% |
|
Tabasco |
291 |
0 |
0% |
|
Tamaulipas |
406 |
2 |
0% |
|
Tlaxcala |
131 |
2 |
2% |
|
Veracruz |
854 |
8 |
1% |
|
Yucatán |
39 |
14 |
36% |
|
Zacatecas |
997 |
12 |
1% |
|
Source: Number of cases referred obtained through public information requests filed by Human Rights Watch. See Appendix I for a complete list of information request numbers. Number of cases opened obtained from National Institute of Statistics and Geography (INEGI), National State Prosecutorial Census (CNPJE) 2023. |
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In addition, many legal advisors told Human Rights Watch that when prosecutors’ offices do refer cases to them, they often do so in ways that make it harder for them to support victims. In one state, for example, a legal advisor explained that the prosecutors’ office frequently sends them notifications of new cases that do not include the contact information of the victim or their family, making it difficult for legal advisors to follow up.
Many legal advisors interviewed by Human Rights Watch said that prosecutors have resisted including them in investigations to avoid scrutiny of their investigative work. As one legal advisor put it:
When we start reviewing case files with family members, we often find that prosecutors have made a lot of mistakes and omissions, like names and dates that are incorrect, evidence that was ignored, or forensic studies that were never ordered. We help the victims file legal documents to request that the prosecutors correct these mistakes. Then the prosecutors get angry with us because we end up creating more work for them. They say “Stop riling up the victim! I’m in charge of this investigation, not you.”
Another said:
When the victims’ commission in our state was first created, we were involved in dozens of homicide cases every week. Now prosecutors refer just three or four cases per week to us. I think it’s because, when we take on cases, we find the deficiencies in their investigation and file requests for them to take additional investigative steps. Now, they only refer families to us when they view them as problematic, like if they are going into the prosecutor’s office every day to ask for updates. The prosecutors get annoyed. They want to get rid of those people, so they send them to us.
Some legal advisors said that when prosecutors do actively involve them in cases, it is often after the initial investigation has been closed and a suspect has already been identified. They explained that judges often refuse to move forward with a criminal case unless there is a legal advisor for the victim’s family present in court. Many legal advisors said they feel they are often brought into the case as a formality, at a stage when they have little chance of helping families to effectively contribute to the investigation. As one legal advisor explained:
Sometimes I get a call at 6:00 p.m. from the courthouse. They say “Here’s this case that’s been open for six months that we never told you about. We just arrested someone. Can you be here in an hour? The judge won’t hold the initial hearing unless the victim’s mother has a legal advisor.” It’s incredible. Why didn’t they tell me six months ago? Why didn’t they tell me when they got the arrest warrant? We can’t help the victim participate in the investigation if they only involve us after the initial investigation is already closed.
Refusing to Provide Access to Information in the Case File
Under Mexican law, victims and their relatives have a right to access the case file, including witness testimonies and physical evidence. This is essential for them to be able to effectively contribute to the investigation and participate in the criminal process. However, victims and their families often face barriers to obtaining that information.
Some of the challenges are logistical. Case files from criminal investigations in Mexico can be hundreds or even thousands of pages long and most prosecutors’ offices in Mexico work primarily with paper records. Many legal advisors said that prosecutors often tell them they do not have enough money to make physical copies of case files to provide to family members and their legal advisors.
In many cases, prosecutors require that families and their legal advisors come to the prosecutor’s office in person to physically review the case file, receive verbal updates, or sign documents requesting that additional investigation be conducted. Yet as some legal advisors pointed out, for low-income families or those from rural areas, it can be costly and time-consuming to miss a day of work and travel to the closest prosecutor’s office. Additionally, in some of the cases Human Rights Watch reviewed for this report, the closest relative of the deceased lived in another part of Mexico or had migrated to the United States, making it extremely difficult or effectively impossible for them to visit the prosecutor’s office in person.
Legal advisors and lawyers from human rights organizations representing victims also said that prosecutors often tell families they do not have time to meet with them or claim, falsely, that they cannot give families information without their legal advisor present. One woman Human Rights Watch interviewed described her efforts to get an updated copy of the case file from the investigation into her daughter’s murder:
I went to the prosecutor’s office so many times and they always told me, “The prosecutor isn’t here right now, but I’ll leave him a message!” I just wanted an updated copy of the case file to go over with my lawyers because it had been over a year since the investigation was opened. It went on like that for five months. Finally, I went there early one morning and waited across the street in my car. When I saw the prosecutor who was in charge of my case walk into the building, I went inside. The receptionist told me the same thing as always, “He’s not here right now!” I said, “Actually, I just saw him walk in the door.” She didn’t know what to do. Finally, a few minutes later she came back and said, “We’re printing off the case file now.” They gave me an updated copy, but the prosecutor never showed his face.
Prosecutors, on the other hand, said that in trying to build cooperation with victims and family members, they need to overcome widespread mistrust of authorities. As one prosecutor said:
People don’t trust the authorities. They think we don’t care and they assume we’re not going to do anything unless they pressure us.
Refusing to Act on Information from Families
Even when victims’ families are able to appoint legal advisors and gain access to case files, it can be difficult for them to effectively participate in investigations. Under Mexican law, victims and their family members have the right to actively participate in the investigation and to request that specific information be included in the case file or that specific investigative acts be conducted as part of the investigation. Prosecutors are legally required to conduct all investigative acts requested by family members that would be conducive to solving the case and to respond to any requests made by victims or their families within three days.
However, prosecutors regularly fail to follow up on information provided by victims and their families in a timely manner, even when it is clearly relevant to the investigation. Legal advisors from state victims’ commissions, private lawyers who represent victims of crime, and lawyers from human rights organizations all said that usually, the most important part of their role representing victims of crime is helping victims to pressure prosecutors to conduct basic parts of the investigation in a timely manner. In the words of one legal advisor from a state victims’ commission:
We always need to go above and beyond to get them to investigate. When victims go to the prosecutor’s office to provide evidence or ask them to conduct an interview, they always make excuses instead of doing it. We are fighting against the authorities who are supposed to be investigating. We have to try to force them to do their job. Either they ignore us, or they find some excuse not to investigate.
Every legal advisor and private lawyer interviewed for this report described multiple examples of cases in which prosecutors had failed to act on important information provided by victims and their families or had outright ignored their requests. A lawyer from a state victims’ commission described one such case:
I’m currently representing a woman whose son was killed. His body was found abandoned by the road. His mother received a message on her phone from an unknown number. It contained a video of a group of people beating up her son. We gave the video to prosecutors and asked them to request information from the phone companies to find out who owned the phone that sent the message. That was 10 months ago. They still haven’t followed up on the case.
In another case, also described by a legal advisor:
I represented the parents of a young man whose body was found abandoned by the railroad tracks in our city. One of his friends approached his parents to say that he knew what had happened and that he wanted to talk to the investigative police. He said he was afraid to go to the prosecutor’s office, but that if the investigators came to the place where he worked, he would talk to them. We gave prosecutors his information so they could interview him. But they never did anything. Eventually, the friend moved away.
Many legal advisors we interviewed from state victims’ commissions said that when family members file requests for additional acts of investigation or requests to re-conduct forensic studies that contain errors, prosecutors often respond by providing arbitrary legal or technical justifications for why they cannot accept these requests, such as telling victims’ families that they have not provided actionable information, without offering other ways of moving the case forward.
One common problem, mentioned repeatedly by both prosecutors and legal advisors, is that prosecutors insist that burdensome requirements be met before they take action in a case, including for example requiring families to provide contact details for witnesses, to justify their requests with legal arguments citing particular statutes or to make their appeals to multiple offices or departments.
Under Mexican law, victims of crime and their family members can file a legal appeal if they believe prosecutors have committed errors or omissions in their investigation, such as by failing to conduct acts of investigation that families believe are necessary to resolve the case. As a result of the appeal, a judge may issue a ruling ordering prosecutors to conduct the acts of investigation requested by victims or their families.
The legal advisors interviewed for this report said this procedure can sometimes be a useful tool to pressure prosecutors into following up on investigations. Typically, they said, once an appeal is filed, a hearing before a judge will be scheduled within two to three weeks. Often, they said, prosecutors attempt to use that time to rectify the omissions in the investigation to avoid being sanctioned by the court. As one legal advisor explained:
Once we file a complaint for excessive delays, prosecutors use the time before the hearing to try to create a kind of legal fiction. They write and send out lots of instructions requesting that investigative police conduct interviews or that forensic technicians conduct studies. Then when the hearing takes place, they have pages and pages of requests. They say ‘Look at everything we’ve done! There are no omissions.’
In some cases, this type of response can be useful if it means that prosecutors conduct pending interviews or take other important investigative steps. However, it is less useful, legal advisors said, when the evidence prosecutors have failed to collect is time-sensitive —for example, security camera footage, which is often automatically deleted after a few weeks.
Mexico’s pervasive corruption permeates the justice system, undermining due process and access to justice. As described below, investigative police, prosecutors and other justice operators often solicit or accept bribes from victims and defendants. While all Mexican states have created mechanisms dedicated to investigating such acts of corruption, these are often weak and have generally failed to prosecute and, when appropriate, sanction prosecutors and others who solicit or accept bribes.
Soliciting Bribes from Victims and Family Members
Investigative police, prosecutors, and other people who work at prosecutors’ offices sometimes solicit money from victims of crime or their family members in exchange for following up on criminal complaints or conducting acts of investigation. In the most recent survey on corruption, conducted by Mexico’s national statistics agency in 2023, around 21 percent of adults in urban areas who had filed a criminal complaint or followed up on an investigation at their state prosecutor’s office that year said they were asked to pay a bribe. The agency estimates that acts of corruption occurred in around a quarter of all interactions between victims and prosecutors in 2023. In 10 states, interactions with prosecutors were among the three most common situations in which people said they were asked to pay a bribe in 2023.
Typically, legal advisors from state victims’ commissions said, investigative police and prosecutors justify these requests by claiming they do not have sufficient resources to investigate if victims and their family members do not give them money. As one legal advisor explained:
What I usually hear from the people we represent is that, in basically every type of crime, the investigative police ask them for money in order to investigate more quickly. Victims and family members tell me, “The officer said he could investigate more quickly if I give him 10,000 pesos (US$487) for gasoline.”
The national statistics agency estimates that the average amount adults in urban areas and their family members spent on paying bribes to prosecutors and investigative police in 2023 was around 8,845 pesos (US$430) per person. For many people in Mexico, this is a significant amount of money and can present a major barrier to accessing justice. The mean monthly household income in Mexico in 2022, the most recent year for which data is available, was 22,437 pesos (US$1,090) per month.
Families who cannot afford to pay this amount of money may decide from the outset not to participate in the investigation, since they assume prosecutors will not follow up on their case unless they can pay, legal advisors said. As one explained:
In a lot of cases I’ve represented, people come to the victims’ commission to ask for help with things like funeral costs. When I start to talk to them about providing information for the criminal investigation, they stop me and say, “The prosecutors already asked us for money, but we don’t have any, so there’s no point. They’re not going to do anything.”
Soliciting or Accepting Bribes from the Accused
State and municipal police, investigative police, and prosecutors sometimes solicit or accept bribes from people accused of crimes, often in exchange for releasing them, not executing arrest warrants, delaying the investigation, “losing” or altering evidence, or reducing the severity of the criminal charges, according to data from Mexico’s national statistics agency and some of the legal advisors interviewed for this report.
In surveys of incarcerated men and women conducted by the national statistics agency in 2020 and 2021, around 16 percent of respondents said that the officials who detained them had asked them to pay a bribe, in exchange either for releasing them or for ensuring they would not be mistreated during their detention. Around 14 percent said they were asked to pay a bribe once they were presented at the prosecutor’s office. The prevalence of corruption is likely much higher, since the survey only included incarcerated people and not those who may have avoided incarceration after paying a bribe.
Many of the legal advisors from state victims’ commissions interviewed for this report described cases they had represented in which victims’ families told them they believed the case would not be prosecuted because the person accused of the crime told them they had paid prosecutors a bribe so they would not advance the case, and the families did not have money to pay a competing bribe. As one legal advisor said:
Often, when we are speaking with the victims’ family, and we tell them it would be helpful for them to give the prosecutors information on the case they say, “Well, the person accused already told me that he gave the prosecutors money, so they won’t move forward with the case. We don’t have any money to give them, so there’s nothing we can do.”
In many cases, legal advisors described situations in which investigators and prosecutors had committed omissions and errors that were so outrageous that the legal advisors believed they could only be explained through corruption. One legal advisor described such a case:
I’m representing a woman who believes her daughter’s boyfriend killed her. We think the boyfriend’s family paid the prosecutor’s office to say it was a suicide. There was a history of domestic violence. The daughter was found covered in bruises and with her front teeth missing but the medical examiner “forgot” to include that in the autopsy report. The report said she had hanged herself. The mother had to get another autopsy done. But then the prosecutors “lost” the new autopsy report. The family gave statements saying there was a history of violence in the relationship but when I got a copy of the case file, they were missing. Instead, it was full of statements prosecutors had taken from the boyfriend’s family saying the daughter had been very depressed, which the victim’s family said was not true. We pushed prosecutors to correct the errors and request an arrest warrant. But when they filed the paperwork, they “accidentally” used the old version of the case file with the old autopsy report. There’s no level of incompetence or disorganization that can explain that. It’s not incompetence. It’s corruption.
Legal advisors also described cases in which they believed that investigative police had accepted bribes in exchange for not executing arrest warrants. A legal advisor described one such case:
In one case I represented, a few years ago, we worked so hard to get an arrest warrant. The family helped the investigative police locate the defendant to arrest him. The investigative police have a special unit just for executing warrants. The officers from that unit went to find him, they detained him, and then they released him a few hours later. They said they forgot to bring a copy of the arrest warrant with them when they detained him, so the arrest was invalid. Maybe it’s true. But it’s such an absurd mistake. How can the special unit for executing arrest warrants forget to bring a copy of the arrest warrant? Some mistakes are too basic to be explained by anything but corruption.
Public defenders also described cases in which they said prosecutors had solicited bribes from their clients in exchange for not pressing criminal charges or for seeking a reduced sentence. As one public defender said:
It’s very common for the prosecutors to ask my clients for money. I’ve had cases—more than one—where families call me and say, “The prosecutors sent us a video of our son killing someone. They said if we give them money they won’t prosecute.” In one case, a few years ago, I represented a member of a criminal group. He had admitted to kidnapping people. He wanted to plead guilty in exchange for reduced jail time. The prosecutors called his family and said “We want to help your son. But we can only accept a plea bargain if you give us 200,000 pesos (US$9,685).” He was in pre-trial detention for years because they thought they could get money out of him.
Ineffective Accountability Mechanisms
All states have some mechanism or mechanisms to address accusations of corruption, abuse, or other wrongdoing by the staff of state prosecutors’ offices. While these mechanisms vary from state to state, all state prosecutors’ offices have an internal affairs unit, Inspector General’s office, or some equivalent. In most states, these units are responsible for receiving complaints against staff, determining whether they have merit and whether the infraction is a criminal or administrative violation and, depending on the rules in each state, either recommending administrative sanctions or recommending that the case be referred to another unit for criminal investigation.
Additionally, since the creation of the National Anti-Corruption System in 2016, all states have been required to establish a state special prosecutor’s office for investigating and prosecuting corruption by public officials, including staff of state prosecutors’ offices. Generally, these anti-corruption prosecutors’ offices have mandates focused on high-level corruption cases or systemic patterns of corruption, rather than individual bribery accusations, although their specific mandates and the types of crime they are responsible for investigating vary from state to state, depending on individual state laws and each of the 32 state penal codes. In most states, victims of corruption or other abuses by staff of state prosecutors’ offices can either file a complaint with the internal affairs units of the prosecutor’s office or can file a criminal complaint directly with the state anti-corruption prosecutor.
As of 2024, all states had established an anti-corruption prosecutor’s office, although, in some, the office only began operating recently. Baja California Sur was the last state to appoint an anti-corruption prosecutor, in March 2023.
These mechanisms have achieved limited impact in investigating corrupt acts and sanctioning those responsible. One challenge is that most people who are victims of corruption or other types of abuse rarely file formal complaints. Mexico’s statistics agency estimates that between 20 and 25 percent of people who interacted with state prosecutors’ offices experienced corruption in 2023. Indeed, that year, state prosecutors’ offices reported receiving around 19,700 complaints against their staff for all types of offenses. However, these likely represent a small fraction of the people who interacted with prosecutors since that year, around 2.2 million criminal investigations were opened. One key reason for this is that, as explained below, many people, including justice operators, believe that these mechanisms will not meaningfully investigate corrupt acts.
Even when victims of corruption or abuse do file complaints, these rarely lead to investigations or sanctions against those responsible. According to the annual prosecutorial census, of the around 22,500 complaints received by internal affairs units at state prosecutors’ offices in 2022, just around 1,200 resulted in administrative sanctions and just under 1,700 cases were referred for criminal investigation.
|
Complaints Filed with Internal Affairs Units of State Prosecutors’ Offices 2022 |
||||
|
State |
Complaints to Internal Affairs Units |
Investigations Opened |
Staff Subject to Administrative Sanctions |
Cases Referred for Criminal Investigation |
|
TOTAL |
22,591 |
9,123 |
1,204 |
1,691 |
|
Aguascalientes |
325 |
115 |
2 |
1 |
|
Baja California |
NO RESPONSE |
501 |
1 |
122 |
|
Baja California Sur |
NO RESPONSE |
NO RESPONSE |
NO RESPONSE |
NO RESPONSE |
|
Campeche |
NO RESPONSE |
NO RESPONSE |
NO RESPONSE |
NO RESPONSE |
|
Coahuila |
282 |
185 |
32 |
96 |
|
Colima |
93 |
148 |
6 |
2 |
|
Chiapas |
460 |
324 |
97 |
9 |
|
Chihuahua |
NO RESPONSE |
NO RESPONSE |
NO RESPONSE |
NO RESPONSE |
|
Mexico City |
12,492 |
3,162 |
513 |
NO RESPONSE |
|
Durango |
NO RESPONSE |
NO RESPONSE |
NO RESPONSE |
NO RESPONSE |
|
Guanajuato |
290 |
32 |
17 |
NO RESPONSE |
|
Guerrero |
396 |
20 |
33 |
14 |
|
Hidalgo |
NO RESPONSE |
NO RESPONSE |
NO RESPONSE |
NO RESPONSE |
|
Jalisco |
NO RESPONSE |
NO RESPONSE |
NO RESPONSE |
NO RESPONSE |
|
Mexico State |
776 |
812 |
96 |
1,005 |
|
Michoacán |
858 |
400 |
21 |
128 |
|
Morelos |
512 |
345 |
31 |
NO RESPONSE |
|
Nayarit |
80 |
93 |
11 |
NO RESPONSE |
|
Nuevo León |
385 |
258 |
60 |
100 |
|
Oaxaca |
12 |
1 |
12 |
NO RESPONSE |
|
Puebla |
3,146 |
1,788 |
17 |
NO RESPONSE |
|
Querétaro |
362 |
92 |
72 |
69 |
|
Quintana Roo |
94 |
18 |
23 |
NO RESPONSE |
|
San Luis Potosí |
409 |
21 |
0 |
90 |
|
Sinaloa |
220 |
95 |
23 |
NO RESPONSE |
|
Sonora |
177 |
17 |
0 |
55 |
|
Tabasco |
618 |
388 |
117 |
NO RESPONSE |
|
Tamaulipas |
152 |
2 |
0 |
NO RESPONSE |
|
Tlaxcala |
NO RESPONSE |
NO RESPONSE |
NO RESPONSE |
NO RESPONSE |
|
Veracruz |
330 |
281 |
15 |
NO RESPONSE |
|
Yucatán |
NO RESPONSE |
NO RESPONSE |
NO RESPONSE |
NO RESPONSE |
|
Zacatecas |
122 |
25 |
5 |
NO RESPONSE |
|
Source: National Institute of Statistics and Geography (INEGI), National State Prosecutorial Census (CNPJE) 2023, Module I, Section V, Questions 6, 10, 15, and 21. |
||||
State anti-corruption prosecutors’ offices have been similarly ineffective. According to a report published in 2022 by the Mexican Institute for Competitiveness (IMCO) and the anti-corruption organization TOJIL, of the around 19,000 investigations opened by state anti-corruption prosecutors against public officials in 2022, just around 4 percent resulted in criminal charges and fewer than 0.2 percent resulted in guilty verdicts.
Lack of Independence
One reason these accountability mechanisms are so ineffective is that, in most states, both internal affairs units and anti-corruption prosecutors’ offices lack independence from the rest of the state prosecutor’s office. Internal affairs units and Inspector General’s offices are part of the prosecutor’s office and, in some states, the head of this office reports directly to the state prosecutor and final decisions about whether to apply administrative sanctions are left to the discretion of the state prosecutor.
Most state anti-corruption prosecutors’ offices also lack independence either on paper or in practice. In 11 states, the anti-corruption prosecutor’s office is considered a unit of the state prosecutor’s office and the head of this office is appointed directly by the state prosecutor, according to a 2022 study by the IMCO and TOJIL.Even in states where the anti-corruption prosecutor’s office has been granted independence on paper, this often does not translate to independence in practice. According to the same study, only six states assigned the state anti-corruption prosecutor’s office its own budget in 2022.In the remaining states, the anti-corruption prosecutor’s office relied on funding assigned to it by the state prosecutor.
Another study, conducted in 2021 by the Washington Office on Latin America (WOLA), found that even in some states where the anti-corruption prosecutor’s office is given independence on paper, decisions about which cases to investigate, how to proceed with investigations, and whether to bring criminal charges required the sign-off of the state prosecutor, creating a conflict of interest when investigating wrongdoing by staff of the prosecutor’s office.
Many of the legal advisors and public defenders interviewed for this report said they did not view filing formal complaints with the internal affairs units or anti-corruption prosecutor’s offices in their states as a useful mechanism for addressing corruption or other abuses by staff of prosecutors’ offices, since they felt it was unlikely these complaints would be impartially investigated. Some said they felt filing such a complaint would be counterproductive, since it could result in retaliation by the staff at their local prosecutor’s office. As one legal advisor explained:
I wouldn’t even bother to file a complaint for corruption because it’s the same institution. It’s the prosecutor’s office investigating itself. They would know I was the one who filed the complaint or encouraged the victim to file the complaint. They would stop giving me access to case files or stop responding to requests regarding my other cases. I can’t create problems just for one case because it would affect all my other cases, all the other victims.
Some legal advisors and public defenders felt that the only institution in their state capable of independently investigating cases of corruption or abuse by state prosecutors was their state human rights commission. These are independent government agencies in each state that have the power to investigate human rights abuses and issue non-binding recommendations calling on authorities to remedy the abuse. State human rights commissions do not have the power to issue sanctions against individual staff members of prosecutors’ offices. However, in some cases, legal advisors felt that the threat of filing a complaint with the state human rights commission could be an effective mechanism to pressure prosecutors to rectify omissions that were the result of corruption. As one legal advisor explained:
Sometimes, when prosecutors or investigative police have done something really egregious, we can get them to correct the omission by sending them a request and CC’ing the state human rights commission. Then the human rights commission can see if they reply and if they fix the problem. It’s a way of saying: whatever the reason for this omission, if you don’t fix it, the victim could file a complaint.
Lack of Staff and Limited Geographical Presence
An additional challenge is that internal affairs units and anti-corruption prosecutors’ offices often have extremely limited numbers of staff and limited geographical presence. In the national prosecutorial census for 2022, 10 states reported having four or fewer staff members in the internal affairs unit dedicated to investigating all types of complaints against staff of the prosecutor’s office.Most states reported that the internal affairs unit had just one office, located in the capital.
In one city where Human Rights Watch conducted research, legal advisors from the local office of the state victims’ commission said that, since their state prosecutor’s internal affairs unit and all its investigators were located in the state capital, if they were to file a complaint against the staff at the local branch of their prosecutor’s office, it would likely be referred back to their local prosecutor’s office for investigation, meaning it would be officials from the local branch of their prosecutor’s office who would be responsible for investigating their colleagues.
|
Staff Investigating Internal Affairs Complaints 2022 |
|||
|
State |
Investigators in Internal Affairs Unit |
Complaints Received |
Complaints per Investigator |
|
Aguascalientes |
3 |
325 |
108 |
|
Baja California |
NO RESPONSE |
NO RESPONSE |
n/a |
|
Baja California Sur |
NO RESPONSE |
NO RESPONSE |
n/a |
|
Campeche |
NO RESPONSE |
NO RESPONSE |
n/a |
|
Coahuila |
4 |
282 |
71 |
|
Colima |
3 |
93 |
31 |
|
Chiapas |
14 |
460 |
33 |
|
Chihuahua |
NO RESPONSE |
NO RESPONSE |
n/a |
|
Mexico City |
32 |
12,492 |
390 |
|
Durango |
NO RESPONSE |
NO RESPONSE |
n/a |
|
Guanajuato |
3 |
290 |
97 |
|
Guerrero |
9 |
396 |
44 |
|
Hidalgo |
NO RESPONSE |
NO RESPONSE |
n/a |
|
Jalisco |
NO RESPONSE |
NO RESPONSE |
n/a |
|
Mexico State |
11 |
776 |
71 |
|
Michoacán |
7 |
858 |
123 |
|
Morelos |
15 |
512 |
34 |
|
Nayarit |
3 |
80 |
27 |
|
Nuevo León |
8 |
385 |
48 |
|
Oaxaca |
5 |
12 |
2 |
|
Puebla |
4 |
3,146 |
787 |
|
Querétaro |
3 |
362 |
121 |
|
Quintana Roo |
4 |
94 |
24 |
|
San Luis Potosí |
7 |
409 |
58 |
|
Sinaloa |
1 |
220 |
220 |
|
Sonora |
1 |
177 |
177 |
|
Tabasco |
5 |
618 |
123 |
|
Tamaulipas |
1 |
152 |
152 |
|
Tlaxcala |
NO RESPONSE |
NO RESPONSE |
n/a |
|
Veracruz |
5 |
330 |
66 |
|
Yucatán |
NO RESPONSE |
NO RESPONSE |
n/a |
|
Zacatecas |
5 |
122 |
24 |
|
Source: INEGI), CNPJE, Module I, Section 5, Questions 2 and 6. |
|||
Lack of capacity is also a problem in anti-corruption prosecutors’ offices. In 11 state anti-corruption prosecutors’ offices, there were five or fewer prosecutors working in 2022 and in 12 states, there were five or fewer investigative police officers assigned to these offices, according to the study conducted by the IMCO and TOJIL. In six states, that meant that each prosecutor in the office dealt with more than 100 new cases per year.
Mexico is a party to core international human rights treaties, including the American Convention on Human Rights and the International Covenant on Civil and Political Rights (ICCPR). These instruments require Mexico to respect a broad range of fundamental human rights, including the right to life. Mexico is also obligated to ensure that victims of human rights violations and abuses, including deprivation of the right to life, have access to simple and prompt recourse through an independent and impartial judicial system that ensures due process.
International human rights law generally applies to states and not directly to private actors, but states are obliged to protect individuals’ enjoyment of rights from impairment by private actors. For example, under the ICCPR states are obliged to take effective steps to protect people against “acts taken by private actors or entities that would impair the enjoyment of covenant rights in so far as they are amenable to application between private persons or entities.”
In order to protect the right to life and ensure that victims of unlawful killings are able to access effective remedy through the judicial system, governments have an obligation to promptly, effectively, and impartially investigate possible homicides with the goal of determining the truth about what happened to the victim, whether the victim’s death was unlawful, and who, if anyone, may be criminally responsible. When a prompt, effective, and impartial investigation reveals that a death was unlawful, authorities have an obligation to ensure that all direct and indirect perpetrators are identified, prosecuted, and, where appropriate, punished through a judicial process.
Investigations and prosecutions of homicides should aim not only to ensure that individual victims can obtain effective remedy through the judicial system but also to prevent perpetrators from committing similar unlawful killings in the future and to generate information authorities can use to design policies aimed at reducing unlawful killings. That means that investigations should aim to identify both direct and indirect perpetrators and, as the Inter-American Court of Human Rights has noted, should aim to identify “patterns of action” and the “structures” involved.
The Inter-American Court of Human Rights has also ordered Mexico “to continue implementing permanent education and training programs and courses in: (i) human rights and gender; (ii) a gender perspective for due diligence in conducting preliminary investigations and judicial proceedings in relation to the discrimination, abuse and murder of women based on their gender, and (iii) elimination of stereotypes of women’s role in society.”
To ensure the right to life, governments also have an obligation to take adequate measures to prevent reasonably foreseeable threats from non-state actors, including organized crime and armed groups. They have an obligation to take appropriate measures to address general conditions in society that may give rise to direct threats to life, such as high levels of crime and gun violence. As part of these obligations, governments need to take steps to disband “irregular armed groups” that are responsible for unlawful killings. They should also take steps to prevent the proliferation of potentially lethal weapons to unauthorized individuals and groups.
Elements of the Duty to Investigate
Authorities have a duty to promptly investigate as soon as they become aware of a potentially unlawful death and to conduct the investigation without unreasonable delays. The investigation should not be dependent on the initiative of the victim or victim’s family, meaning that authorities should not wait for the victim or victim’s family to file a formal criminal complaint and should not rely on the victim or victim’s family to conduct acts of investigation or provide evidence.
Simply opening an investigation is not sufficient to comply with the duty to investigate under international law. As the Inter-American Court of Human Rights explained in its 2009 sentence finding that Mexican authorities had failed to effectively investigate a pattern of disappearances and killings of women in Ciudad Juárez, Chihuahua:
The duty to investigate is an obligation of means and not of results, which must be assumed by the State as an inherent legal obligation and not as a mere formality preordained to be ineffective. The State’s obligation to investigate must be complied with diligently in order to avoid impunity and the repetition of this type of act. In this regard, the Tribunal recalls that impunity encourages the repetition of human rights violations.
International law establishes specific criteria regarding effective and thorough homicide investigations. These criteria are laid out in detail in the Minnesota Protocol on the Investigation of Potentially Unlawful Death and have been reiterated in rulings by the Inter-American Court of Human Rights and in general comments by the UN Human Rights Committee. An effective and thorough homicide investigation is one in which authorities take all reasonable steps to:
i) Identify the victim(s);
ii) Recover and preserve all relevant evidence regarding the cause of the death, the identity of the perpetrator(s), and the circumstances surrounding the death;
iii) Identify all possible witnesses and obtain information from them relating to the circumstances surrounding the death;
iv) Determine the cause, manner, place, and time of the death; and
v) Determine who was involved in the death and their individual responsibility for the death.
Homicide investigations should be independent, impartial, and aimed at determining the truth about what happened to the victim. Authorities should collect and review all evidence, without bias, and consider both exculpatory and inculpatory evidence. Investigations or prosecutions that are biased, deliberately exclude evidence, or use evidence or testimonies that have been altered, fabricated, or obtained through threats or torture, are incompatible with the obligation to verify the facts related to the victim’s death, ensure the perpetrator is held accountable, and take steps to prevent the perpetrator from committing future unlawful killings.
Family members of homicide victims have the right to simple and prompt recourse and reparation through the judicial system. As discussed in more detail in this report, they have the right to seek and obtain information about the causes of the victim’s killing, to participate in proceedings, and to learn the truth about the circumstances and events that led to it.
Rights of the Accused
Mexico is a party to international treaties which obligate it to ensure due process and prevent and investigate cases of torture or ill-treatment. People accused of crimes, including homicide, have the right to a fair and public hearing before a competent, independent, and impartial court. They must be presumed innocent until proven guilty, which means it is the responsibility of authorities to obtain and present sufficient evidence to demonstrate, beyond a reasonable doubt, that the defendant has committed the crime of which they are accused. Authorities should not make public statements affirming the guilt of the person accused of the crime before a trial has been concluded or implying that placement in pre-trial detention is an indication of guilt.
People accused of crimes should be immediately informed, in detail, of the criminal charges against them. When arrested, they should be brought before a judge as soon as possible and should only be placed in pre-trial detention upon the order of a judge. They have the right to be tried without undue delay and to not be held for an extremely prolonged period of time in pre-trial detention. People being held in pre-trial detention must be tried as expeditiously as possible.
Under international human rights law, pre-trial detention should not be applied automatically to all people accused of crimes. It should only be used in exceptional cases, based on an individualized determination that it is necessary for purposes such as preventing flight, interference with evidence, or the recurrence of crime. The Inter-American Court of Human Rights has ruled that Mexico’s automatic application of pre-trial detention to all people accused of certain categories of crime, such as homicide, violates international human rights standards.
Mexican authorities are also obliged to ensure that no one is tortured, subjected to cruel, degrading or inhumane treatment, prosecuted, or convicted based on evidence obtained through such human rights violations. Authorities have an obligation to promptly, effectively, and impartially investigate any allegations of torture or mistreatment made against public officials.
To Congress:
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Amend the General Law on the National Public Security System to include a requirement that all state police forces and prosecutors’ offices create external control mechanisms with the authority to review allegations of misconduct and recommend sanctions or rules changes.
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Amend the General Law on the National Public Security System to require that all state public security systems develop a state criminal policy and that all state prosecutors’ offices develop a meaningful criminal prosecution plan. These plans should be developed in an open, public, and collaborative process, in cooperation with state public security officials, academics, civil society organizations, and other experts.
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Repeal the provisions in the Constitution and the National Code of Criminal Procedure requiring judges to automatically order the pre-trial detention of people accused of homicide, femicide, and other crimes once a vinculación a proceso has been issued.
To the Attorney General’s Office:
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Implement all pending measures in the Ley General en Materia de Desaparición Forzada de Personas y de Desaparición Cometida por Particulares. This includes ensuring that the Banco Nacional de Datos Forenses (BNDF), the Registro Nacional de Fosas Comunes y de Fosas Clandestinas, and the Base Nacional de Información Genética (BaNIG) are all fully functional.
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Refrain from presenting criminal charges against judges in retaliation for their rulings.
To the National Public Security Council and the National Conference of Prosecutors:
Take steps to improve human and material capacity in state prosecutors’ offices and forensic services departments. These could include:
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Establishing recommendations regarding maximum caseloads and minimum staffing requirements in the homicide units of state prosecutors’ offices, based on geographic coverage, population, and homicide rates.
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Establishing recommendations regarding the minimum level of staffing and equipment required and maximum recommended caseloads in key forensic specialties, depending on the complexity of cases, and including specific guidelines on the types of equipment and materials that should be provided to forensic technicians.
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Establishing national standards regarding the types of professional qualifications that forensic technicians and other experts should hold, depending on their forensic specialty.
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Establishing national standards regarding the rules and legal frameworks governing recruitment, promotion, adscription, salaries, and removal from the professional career services in state prosecutors’ offices.
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Conducting, with the assistance of the Comisión Nacional de los Salarios Mínimos (CONASAMI), an evaluation of the salary and compensation of staff at state prosecutors’ offices (similar to the evaluation conducted for state and municipal police). The results of the evaluation should be made public and include recommendations to state and federal authorities to ensure that all staff receive appropriate compensation.
Take steps to strengthen the investigation of homicides by state prosecutors’ offices. These could include:
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Establishing a standard protocol for the investigation of intentional homicides, which could include:
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A set of minimum investigative steps and forensic studies that should be carried out automatically soon after a homicide is reported.
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A recommendation that prosecutors hold face-to-face meetings with the local police, investigative police officers and forensic technicians who responded to the crime scene or who are participating in the investigation to discuss possible theories of the case and decide on lines of investigation.
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A recommendation that all witness interviews conducted in intentional homicide investigations be audio- or video-recorded.
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Assisting state prosecutors’ offices in developing metrics they can use to evaluate the performance of prosecutors and investigative police officers in homicide investigations, with the goal of encouraging authorities to conduct thorough, impartial, and rights-respecting investigations of crimes, rather than measuring performance based on numerical outcomes at specific stages of the criminal process.
Take steps to assist state prosecutors’ offices in strengthening internal control mechanisms to ensure that torture, corruption, and abuses are effectively investigated and sanctioned. These could include:
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Conducting an evaluation of the effectiveness of internal control authorities in state prosecutors’ offices, focused on identifying practices, structures, and procedures that limit the independence and effectiveness of these mechanisms. The results of the evaluation should include recommendations on how state prosecutors’ offices and state legislatures can improve the effectiveness of their internal control authorities.
To the State Legislatures:
Take steps to ensure state prosecutors’ offices have sufficient, qualified, trained staff to effectively respond to and preserve crime scenes and investigate homicides. These could include:
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Ensuring that state laws require the establishment of real professional career services in state prosecutors’ offices, with clear and objective rules governing the recruitment, selection, promotion, compensation, and removal of staff. These rules should meet the minimum requirements set out by the General Law on the Public Security System. They should include:
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A requirement that all staff who enter the professional career service are selected through an open, competitive, merit-based recruitment process, based on clear, objective rules set out in a regulatory document approved by the state legislature.
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A requirement that all staff who enter the professional career service undergo an anti-corruption vetting process.
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The establishment of minimum standards regarding the types of qualifications that prosecutors, investigative police officers, forensic technicians, and other staff members should hold.
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The establishment of an open, competitive, merit-based process for advancement within the prosecutor’s office, based on clear objective standards.
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The establishment of clear rules regarding the termination of staff from the professional career service based on objective, legally binding standards, including protections against arbitrary removal of staff for political or personal reasons. There should be clear rules and effective systems to remove or sanction staff who are found to have committed abuses.
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Take steps to improve oversight of state prosecutors’ offices, strengthen internal control mechanisms, and ensure that torture, corruption, and abuses are effectively investigated and sanctioned. These could include:
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Amending state laws to create effective external control mechanisms at all state prosecutors’ offices with the authority to review allegations of wrongdoing and recommend sanctions or rules changes.
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Ensuring that all state anti-corruption prosecutors’ offices have full legal, operational, and budgetary autonomy to enable them to effectively investigate and prosecute allegations against staff of state prosecutors’ offices.
Take steps to ensure victims and their family members are able to effectively participate in investigations. These could include:
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Ensuring that all state victims’ commissions have sufficient staff, resources, and materials to effectively enable victims of crime and their family members to participate in investigations.
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Taking steps to improve coordination between prosecutors’ offices and state victims’ commissions to ensure that victims’ commissions are immediately aware of all new homicide and femicide investigations that are opened and are provided with sufficient information to easily contact victims’ families.
Take steps to ensure those accused of homicide have access to an effective defense and receive a fair trial. These could include:
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Taking steps to protect the independence of state public defenders’ offices, such as by granting them independence from the state judiciary and the state prosecutors’ office.
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Ensuring that public defenders’ offices are given sufficient funding, resources, and staff to effectively represent all defendants and to conduct investigations on behalf of defendants.
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Taking steps to protect the independence of judges when redacting amendments to the state constitution and secondary laws to implement the changes to the judicial system approved in September 2024. These could include:
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Ensuring that the selection committees choosing candidates for judicial elections base their decisions on objective standards, such as the professional merit and independence of candidates.
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Ensuring that state laws establish clear, objective criteria for the sanction and removal of judges by judicial disciplinary tribunals and that they prohibit the removal of judges in retaliation for their decisions in specific cases.
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To State Prosecutors’ offices:
Take steps to improve the capacity to investigate homicides and improve coordination between prosecutors, investigative police, and forensic technicians. These could include:
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Ensuring there are specialized units for investigating and prosecuting homicides and that these units are given sufficient staff and resources.
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Ensuring that staff in homicide units receive specialized training related to homicide investigations, including training on the use of advanced investigative methods.
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Establishing incentives to encourage the most qualified and rights-respecting prosecutors and investigators to work in homicide units and establishing merit-based selection processes to determine which officials are assigned to these units.
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Ensuring that all forensic technicians, prosecutors, and investigative police officers complete the minimum training course set out by the Programa Rector de Profesionalización before they begin working on cases.
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Establishing metrics to evaluate the performance of prosecutors and investigative police officers that are based on the extent to which they conduct thorough, impartial, and effective investigations, rather than on numerical outcomes at specific stages of the process.
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Establishing procedures in homicide units to improve coordination between the prosecutors, investigative police officers, and forensic technicians who are working on the same case. These could include efforts to encourage these officials to hold meetings to discuss evidence and theories of the case and to decide on which lines of investigation to pursue.
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Developing criminal prosecution plans with clear standards to help prosecutors better determine how to prioritize cases.
Take steps to strengthen internal control mechanisms to ensure that torture, corruption, and abuses are effectively investigated and sanctioned. These could include:
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Strengthening the independence and authority of internal control bodies.
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Ensuring internal control bodies have sufficient staff and resources to effectively investigate accusations of wrongdoing.
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Ensuring there are clear and objective rules regarding the sanction or removal of officials who have been found guilty of wrongdoing.
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Creating external oversight mechanisms with the authority to review allegations of wrongdoing and recommend sanctions or rules changes.
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Requiring that all witness interviews be audio- or video-recorded and that witness statements be transcribed verbatim.
Take steps to ensure victims and their family members are able to effectively participate in investigations. These could include:
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Ensuring that all families of homicide victims are referred to their state victims’ commission.
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Developing systems to ensure that state victims’ commissions are made aware of all new homicide investigations and are able to easily contact victims’ family members.
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Ensuring that families and their legal advisors are able to easily access case files, such as through an electronic system.
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Ensuring that all prosecutors working on homicide and femicide cases receive training on revictimization and gender stereotypes, how to avoid these practices, and how they can negatively affect investigations.
Take steps to ensure victims, their family members, and witnesses are protected against retaliation. These could include:
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Ensuring that state witness protection laws are effectively implemented.
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Creating specialized units to quickly evaluate and implement protection requests and ensuring these units have sufficient staff and resources to operate effectively.
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Ensuring victims and witnesses are able to access a broad range of protection options including police protection, assistance to strengthen home security measures, assistance to install security systems or cameras, panic buttons, temporary relocation assistance, and protective accommodation for both men and women.
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Explore ways to continue providing protection measures to victims and witnesses after a criminal case has concluded if necessary.
To State Governments:
Take steps to improve protection for victims and witnesses. These could include:
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Ensuring that state and municipal police forces are able to quickly and effectively implement all protection requests by creating specialized units within these forces responsible for implementing protection measures.
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Ensuring victims and witnesses can access a broad range of protection options, such as: security systems, panic buttons, temporary relocation assistance, and protective accommodation for both men and women.
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Explore ways to continue providing protection measures to victims and witnesses after a criminal case has concluded if necessary.
Take steps to ensure state and local police effectively respond to and preserve crime scenes and to improve coordination between police and prosecutors. These could include:
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Ensuring that all state and municipal police officers complete a training program approved by the Executive Secretary of the National Public Security System before being deployed.
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Ensuring that all police officers receive specific training in responding to and preserving crime scenes and are provided with the materials to do so.
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Establish coordination mechanisms to enable state and municipal public security departments to coordinate and proactively share information with prosecutors’ offices.
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Establish facilities for the long-term storage and identification of unidentified or unclaimed human remains.
To the United States:
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Prioritize support for efforts to improve investigative and forensic capacity in state prosecutors’ offices in Mexico and efforts to improve training for staff of public defenders’ offices and state victims’ commissions.
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Prioritize support for efforts to facilitate and strengthen forensic and human identification capacity in Mexico.
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Take urgent efforts, in cooperation with the Mexican government, to stem the illegal flow of firearms from the United States to Mexico.
This report was written and researched by Tyler Mattiace, Mexico researcher.
It was reviewed and edited by Juanita Goebertus, Americas director; Juan Pappier, Americas deputy director; Sari Bashi, program director; Joseph Saunders, deputy program director; Chris Albin-Lackey, senior legal advisor; Macarena Sáez, Women’s Rights director; Cristina Quijano Carrasco, Women’s Rights researcher; Carlos Ríos Espinosa, Disability Rights associate director; Brian Root, senior quantitative analyst; Delphine Starr, Americas editorial officer; André Rangel, Americas associate communications director; Johan Romero, Americas senior associate; and Santiago Menna, Americas senior research assistant. Maria McFarland Sánchez-Moreno contributed to the planning of this report.
Travis Carr, publications officer, and José Martínez, senior administration coordinator, prepared this report for publication. Ivana Vasic, senior graphic designer and Laura Navarro Soler, information designer, created the graphics for this report.
Human Rights Watch would like to thank the prosecutors, investigators, forensic technicians, public defenders, legal advisors, lawyers, human rights organizations, and many other justice operators and independent experts who gave their time, invited us into their offices and courtrooms, and shared their experiences and insights for this report. We are also particularly grateful to the attorneys general and heads of state victims’ commissions who agreed to allow Human Rights Watch to conduct interviews with their staff.
Most of all, we are grateful to the family members of victims who generously shared their stories with us in hopes that doing so might help build a fairer and more effective and rights-respecting justice system for all Mexicans.
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