(Editor’s Note: This article is part of the Just Security symposium “Thinking Beyond Risks: Tech and Atrocity Prevention,” organized with the Programme on International Peace and Security (IPS) at the Oxford Institute for Ethics, Law and Armed Conflict. Readers can find here an introduction and other articles in the series as they are published.)
After then-President Felipe Calderón declared a war on drugs in 2006, drug-related violence in Mexico escalated sharply. His aggressive strategy, which involved deploying military forces to combat drug trafficking, sparked widespread confrontations between State security forces and organized crime groups. This approach destabilized power structures within these groups, provoking violent turf wars as factions vied for territorial control. Violence surged as a result, leading to a dramatic rise in homicides and disappearances. Since 2006, Mexico has recorded at least 431,000 homicides and more than 117,000 disappearances, with over than 80 percent of these cases occurring in the last 15 years.
Widespread disappearances are one of the most harrowing dimensions of Mexico’s ongoing drug war. Thousands of people, often targeted by organized crime groups or caught in the crossfire, vanish without a trace, leaving countless families in anguish. Far from curbing such criminal activities, the war on drugs has only intensified them and worsened the country’s wider humanitarian crisis, creating insecurity and fear nationwide.
In response to this crisis and the government’s failure to adequately address it, families of the missing have formed search groups in different regions throughout Mexico. These groups, mainly composed of women, have scoured vast areas of the country, learning to identify signs and patterns in nature that might indicate clandestine graves — hidden or secret burial sites used to conceal bodies.
While a remarkable feat, these searches are dangerous and time-consuming. The FOUND Project has shown in Mexico’s Jalisco region that existing technologies, such as multispectral cameras and drones, can replicate these search groups’ methodology more safely and efficiently. By integrating these technologies, official missing persons agencies can respond more effectively to the rising number of disappearances, reducing the uncertainty and agony for families while minimizing risks to search groups.
Moving forward, official search operations in Mexico and other countries should incorporate drones and multispectral analysis, expand testing in other regions, and establish collaborative frameworks that include the participation of these search groups.
Disappearances in Mexico: Pervasive, But Overlooked by the State
Organized crime groups disappear people for several reasons: to maintain control, instill fear, and avoid legal charges. They often target members of rival groups, suspected informants, or those who owe them money, as well as their own members who disobey or betray them. In some cases, disappearances are linked to human trafficking operations, with victims forced into labor, sexual exploitation, or other forms of modern slavery to benefit the cartel’s financial interests. Beyond eliminating forensic evidence, disappearances convey a menacing message to other criminal groups, authorities, and civilians that disloyalty will not be tolerated and that anyone who crosses them risks severe consequences, including death.
In Mexico, disappearances are linked not only to cartels but also to the State. These are referred to as “enforced disappearances”: when government agents or their proxies arrest, detail, or abduct someone, then refuse to acknowledge doing so and conceal the person’s fate and whereabouts. This practice places the person outside the protection of the law, often enabling grave human rights violations, including torture, inhumane treatment, and extrajudicial killings.
Disappearances, whether perpetrated by the State or cartels, are a critical human rights issue in Mexico today. Victims include not only those involved in criminal activities, but also human rights activists, journalists, migrants, and innocent civilians. The persistent lack of accountability and failure to investigate and prosecute these cases have created a pervasive sense of impunity and insecurity across the country. Criminals in Mexico engage in unlawful activities due to the minimal likelihood of apprehension, as reflected in a staggering 99 percent impunity rate. This culture of impunity not only emboldens criminal organizations but also erodes public trust in authorities, perpetuating a cycle of violence and fear.
Due to the government’s failure to conduct adequate investigations or provide meaningful support to affected families, family search collectives have taken matters into their own hands. For over fifteen years, search groups have united across Mexico to share resources, conduct searches, and pressure authorities to act. These grassroots organizations not only work to find their missing loved ones, but also strive to raise awareness about disappearances and hold the government accountable for its inaction. Through demonstrations, social media campaigns, and collaborations with experts and human rights organizations, they have become a powerful voice advocating for change, transparency, and the adoption of effective policies to prevent future disappearances. Authorities can and should learn from the strategies used by search groups.
Locating Clandestine Graves: Lessons from Family Search Groups
Most search groups for disappeared persons in Mexico are made up of women, largely due to traditional gender roles that position them as caregivers. When a loved one goes missing, women – especially mothers, sisters, and wives – often take on the responsibility of searching, while men, as primary earners, may have less time to participate. Women also tend to be viewed as less threatening by authorities, which can help them navigate institutional barriers.
Womens’ search groups currently use their empirical knowledge to identify potential clandestine graves. For example, in open areas, they look for natural indicators – called signs – such as off-season green plants or unusually blooming flowers, which may signal bodies are buried below. They then insert a T-shaped metal stake into the ground and smell it upon removal to detect any scent of decomposition. If decomposition is detected, they proceed to recover the remains.
In other settings, like abandoned houses, women tap the cement floor with the same metal stake – known as a vidente (seer or clairvoyant) – listening for changes in sound that could indicate an anomaly, such as a hollow space, and potentially, a body. Upon detecting any anomaly, they break through the floor and again use the stake to check for decomposition.
The FOUND project, launched in 2023, is helping tackle Mexico’s crisis of disappearances by combining the research expertise of these search groups with advanced technology. Based in Jalisco, the state with highest number of recorded disappearances (more than 16,000), FOUND is testing a range of technological methods – including multispectral and thermal imaging, seismic noise analysis, electrical resistivity tomography, forensic entomology and botany, territorial analysis, and soil studies – to help locate clandestine graves.
To test these tools, FOUND established two experimental sites in Jalisco, in Tonalá and Cajititlán. These sites simulate real burial scenarios by burying pig carcasses subjected to conditions such as extreme heat, fragmentation, and being wrapped in plastic or blankets. Preliminary results showed that, in line with the findings of family collectives, body decomposition alters the soil’s moisture and produces nitrogen-rich areas, often visible in unusual plant growth such as off-season green plants or unexpected blooming flowers.
Crucially, these nutrient anomalies can be detected using multispectral cameras, which identify nitrogen and chlorophyll anomalies in plants by measuring subtle differences in light reflections. Though traditionally used in agriculture to monitor plant development and health, this technology can be adapted for detecting clandestine graves by using vegetation indices, such as the Nitrogen Accumulation Index (NAI). Attaching multispectral cameras to drones has allowed for consistent and thorough monitoring of both experimental sites, making it easier to identify anomalies — and potentially, in the future, clandestine graves.
Building on these findings from experimental sites, the Jalisco Search Commission integrated drones and multispectral analysis into its official search practices in May 2024. Since June, FOUND has been testing tomography devices and high-frequency seismic noise instruments for locating underground anomalies, especially under concrete layers. FOUND is now sharing its findings, and in July began training the Colombian government’s Missing Persons Unit and the office of Mexico’s Attorney General in Zacatecas on using multispectral analysis in searches.
Improving Official Search Mechanisms
The FOUND Project offers important insights that authorities should consider to improve their response to the crisis of disappearances in Mexico and elsewhere.
First, integrating drones and multispectral analysis into official search operations could improve their efficiency and reduce dangers to search groups. The successful use of these technologies has demonstrated their potential to cover large areas quickly, reducing the time and risk associated with searching in locations controlled by organized crime groups. By using drones and multispectral cameras, authorities can scan more safely, minimizing the danger faced by search teams.
Second, investing in experimental sites in other regions and countries is crucial. The success seen at sites in Jalisco underscores the importance of controlled environments for testing and refining search technologies and methods. Expanding these sites to other regions in Mexico and beyond, while tailoring them to local conditions, will allow refinements in protocols before they are rolled out more broadly.
Finally, these frameworks must be developed collaboratively, including with unofficial search groups. The partnership between women’s search groups and the FOUND project highlights the importance of building community trust. Authorities should prioritize collaboration with grassroots groups to ensure that technological advancements are informed by on-the-ground experiences. This approach not only validates the knowledge and experiences of these groups, but also contributes to restoring the trust lost in authorities who have failed to protect their loved ones.