Relatives and friends of 43 teachers college students who disappeared last year wait in Mexico City for a group of experts convened by the Inter-American Commission on Human Rights to present the conclusions of its investigation. (Omar Torres/AFP/Getty Images)

Nearly a year after 43 students at a Mexican teachers college disappeared, an examination of the case by outside experts has rejected the government’s official narrative of events and claims that investigators tortured witnesses and mishandled evidence.

The report, more than 400 pages long, does not shed light on the fate of the students, but it calls into question nearly all the claims by Mexican authorities about how the crime unfolded in the troubled hills of Guerrero state, particularly the assertion that the students were burned to death at the base of a rural trash dump.

The review, conducted over six months with the Mexican government’s cooperation by a group of experts convened by the Inter-American Commission on Human Rights, also proposed a possible new motive: that the students may have inadvertently stolen a bus full of drugs and that corrupt police officers wanted it back.

“This report provides an utterly damning indictment of Mexico’s handling of the worst human rights atrocity in recent memory,” José Miguel Vivanco, Americas director at Human Rights Watch, said in a statement. “Even with the world watching and with substantial resources at hand, the authorities proved unable or unwilling to conduct a serious investigation.”

The Ayotzinapa students’ case marked a turning point for the presidency of Enrique Peña Nieto, generating months of street demonstrations and establishing that the drug-war atrocities that his government had hoped to leave in the past remained alive and well. Throughout all the upheaval, the parents of the students rejected the government’s version of events and clung to hope that their children were alive.

Mexican Attorney General Arely Gómez González told reporters on Sunday that the government remains committed to getting to the bottom of the Ayotzinapa case and that the investigation will incorporate the report’s findings. She highlighted the areas of convergence between the government’s recommendation and the outside report, such as the conclusion that “the municipal police of Iguala and Cocula participated in the commission of these crimes.”

“The government of the republic reiterates its commitment to Mexican society, and particularly to the victims’ families, to continue working to clear up the facts,” she said.

Gómez added that the mandate of the experts’ group will be extended to allow them to complete their work.

Since then-Attorney General Jesús Murillo Karam stood before reporters in November with videos of witness testimony, the official story has been that the teachers college students from Ayotzinapa were captured by police in the town of Iguala and handed over to drug cartel assassins, who shot them and burned their bodies in a remote trash dump outside the nearby town of Cocula. More than 100 people have been arrested in the case.

But first Argentine forensic investigators working on behalf of victims’ families and now this team of investigators, including former Guatemalan attorney general Claudia Paz y Paz and other Latin American lawyers, have discounted key aspects of that theory. The latter conducted their work with the blessing of the Mexican government. They interviewed prisoners, witnesses and government officials, and they brought in experts, including a Peruvian fire expert who studied the Cocula dump, to analyze crime scenes.

Charred remains of one of the students have been identified, but doubts remain about where those remains were found.

In the Cocula dump, “there wasn’t a fire of that magnitude,” Francisco Cox, a Chilean lawyer who worked on the report, said in an interview.

All the people arrested in the case, Cox said, “deny any involvement” and “said that they were tortured.” Some of them have complained to Mexico’s human rights commission.

There were other seeming lapses during the course of the investigation: Clothes of the victims found by authorities had not been examined, and surveillance videos were erased.

Authorities have said that the initial conflict with police came because the students stole buses in Iguala to disrupt a speech by the mayor’s wife, María de los Angeles Pineda. Authorities accused the couple of ordering police to get rid of the students. Both the mayor and his wife are in jail.

But the experts’ group noted that Pineda’s speech ended an hour and a half before the students arrived in Iguala on the night of Sept. 26. Instead, there were signs that the Iguala buses were used to transport heroin into the United States. When the students stole five of them — a rather common occurrence for this college — they may have inadvertently taken one packed with drugs. That could explain the aggressive hunt by police to find the buses and stop them from leaving the city.

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