It remains unclear exactly how 43 students from a rural teacher’s college in Mexico disappeared three years ago. And much of what is known about the case has come not from the Mexican government, but rather from investigations by journalists and non-governmental groups, illustrating the state’s failure to clarify one of the most shocking instances of criminality in Mexico’s recent history.

In the evening hours of September 26, 2014, 57 students from the Ayotzinapa Rural Teachers’ College disappeared in the city of Iguala in the western state of Guerrero. Fourteen of the missing students were found days later on September 30, but there were no signs of the remaining 43.

In January 2015, the Mexican government concluded that municipal police in the city of Iguala had intercepted the students, leading to a confrontation that killed six people, injured 25 and left several vehicles destroyed. The government’s “historical truth” determined that Iguala police had handed the students over to a local criminal group known as the Guerreros Unidos, who had allegedly mistaken the students for rival gang members.

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Felipe Rodríguez Salgado, alias “El Terco” or “El Cepillo,” the alleged leader of the Guerreros Unidos, later testified that he had ordered the students to be killed and their bodies burned at a trash dump in the nearby town of Cocula.

However, several investigations by independent experts cast doubt on the government’s version of the events. For instance, investigators have found that the evidence at the trash dump did not correspond with temperatures needed to burn 43 bodies, government witnesses had varying versions of the events, and doubts remained regarding who actually ordered the students’ apparent murders.

More than 100 people have been arrested for their alleged involvement in the students’ disappearance, but the case remains unsolved.

InSight Crime Analysis

Much of what is known about the fate of the Ayotzinapa students has come from journalists and civil society groups. This can be viewed as a testament to these actors’ commitment to finding the truth, but also as a sign that the Mexican government has failed to advance — much less solve — this case.

In fact, there is mounting evidence that the Mexican government has not only failed to fulfill its obligation to properly investigate the disappearance of the 43 students, but that officials have actively attempted to block the progress of various probes into the incident. Government bodies reportedly refused to hand over evidence to a team of independent international investigators, who were targeted by spying software and subjected to a smear campaign meant to undermine their work.

Maureen Meyer, the senior associate for Mexico at the Washington Office on Latin America (WOLA), described the government’s failures in the case as “unjustifable.”

“The lack of progress in a case that the Mexican government has called ‘the most exhaustive investigation in the history of Mexico,’ along with mounting evidence that public officials obstructed justice and impeded the investigation, has come to symbolize the widespread impunity found within Mexico’s troubled criminal justice system and the government’s lack of political will to credibly investigate and sanction human rights violations,” Meyer said in a press release.

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On the other hand, a number of journalistic investigations have uncovered key details about the Ayotzinapa case, and have kept it in the international spotlight.

Earlier this month the Forensic Architecture independent research agency based at Goldsmiths, University of London, released an interactive platform that transposes “publicly available investigations, videos, media stories, photographs and phone logs” into thousands of data points that map the different incidents that took place on the night of the confrontation and in the days following the disappearance of the 43 students. The researchers say their visualization demonstrates the “level of collusion and coordination between state agencies and organized crime throughout the night.”

Given the Mexican government’s demonstrated inability or unwillingness to get to the bottom of this tragic incident, it appears that independent initiatives like these will continue to be crucial to uncovering what really happened that night in Iguala.