Julio Cesar Mondragon’s body was found on a dirt path in the city of Iguala a day after the students were attacked and abducted by police in league with the Guerreros Unidos gang in September 2014.
Reports initially suggested that the gang had skinned Mondragon’s face.
But the National Human Rights Commission issued a report Monday saying that a scientific analysis of the autopsy and pictures of the body showed that there were no signs that the face was cut by a knife.
There are indications of bites and paw prints from dogs and rodents, the commission said in its report.
Jose Larrieta, who heads the commission’s Iguala investigation, said Mondragon died of head trauma after he endured “physical torture and he was brutally beaten with viciousness and cruelty due to the joint action and complicity of” 10 drug gang members and an official from the city’s public safety and civil protection department.
Later, the Argentine Forensic Anthropology Team, which participated in Mondragon’s second autopsy at the request of his family, said that the lack of skin in his face was due to “fauna activity” but it added that there were also “areas with suspected intervention of a sharp object.”
The authorities say the 43 other students were killed by the Guerreros Unidos, who incinerated their bodies at a garbage dump and dumped their remains in a river.
But the government’s investigation has been questioned by international rights group and independent experts from the Inter-American Commission on Human Rights, who say that there is no scientific proof of a large fire at the dump.