MEXICO CITY - While Mexican prosecutors declared last year that 43 missing students were incinerated at a landfill, official documents published Sunday show that one gang suspect testified that at least nine were slaughtered elsewhere.
Mexico's attorney general office posted on its website the 54,000 pages of documents from the much-criticised investigation into a case that has bedevilled President Enrique Pena Nieto's administration.
A review by AFP of hundreds of pages found contradictory testimony among some of the more than 100 suspects who have been detained, including Guerreros Unidos drug cartel members and municipal police officers.
The report -- divided into 85 tomes and 13 annexes with several redacted names and paragraphs -- was made public by Attorney General Arely Gomez following freedom of information requests from journalists. It is rare for Mexican authorities to make investigative documents public online.
Gomez's predecessor, Jesus Murillo Karam, concluded late last year that police in the southern city of Iguala attacked the students on September 26, 2014, after they had seized buses for a protest in Mexico City.
Murillo Karam said the officers abducted 43 students and handed them over to the Guerreros Unidos drug gang, which confused them with rivals, killed them and incinerated their bodies at a garbage dump in the neighbouring town of Cocula.
But parents of the students have never accepted the official conclusion.
Last month, independent experts from the Inter-American Commission on Human Rights tore apart the official investigation. They said there was no scientific evidence that the 43 students were burned to ashes at the landfill.
Tomas Zeron, the prosecutors' chief of investigations, insisted that a "large" number of students were incinerated at the dump, although he acknowledged that he could not confirm whether it was all 43.
Killed on a hill
But the newly released documents include the testimony of Marco Antonio Rios Berber, a confessed member of the Guerreros Unidos, who said 13 students were taken to a hill on the outskirts of Iguala, where at least nine were killed.
Rios Berber testified that he was ordered to buy diesel fuel and that when he returned, three students had been shot in the head by two other gang members, including one nicknamed "Chuky" or "Choky."
"That's for being rebellious," Chuky said, according to Rios.
The bodies were tossed in a pit and incinerated with the diesel. A vehicle arrived later with the 10 other students.
"I shot two in the head" and four more were killed by other gang members, Rios said. He added that the six bodies were thrown in the pit, incinerated and covered with dirt and tree branches.
"They left the four others tied up. They had beaten them and left the unconscious," he testified. He said he went home at 3:00 am on September 27 and did not know what happened to the other students.
The attorney general's office was not immediately available for comment.
In October 2014, Guerrero state prosecutors said hitmen confessed to killing 17 students and burying their bodies on the same Pueblo Viejo district.
A mass grave was found on the hill that same month with 28 bodies inside.
But DNA tests showed none belonged to the students but rather to victims from other cases.
15 dead asphyxiated
The newly released file includes other testimonies that Murillo Karam used to conclude that the 43 students were killed and incinerated in Cocula, though even those stories had some contradictions.
One suspect said he saw around 30 students transported in a truck to the landfill while another saw around 40. Neither gave a precise figure.
Confessed hitman Jonathan Osorio Cortes, alias "Jona," said 15 students were already dead when they arrived at the dump because they died from asphyxiation from being piled on top of each other in the back of the truck.
Another one arrived dead with bullet wounds.
The survivors were either shot in the head or beaten to death with a tree trunk, he said. Their bodies were then burned in a funeral pyre of wood, tires and diesel.
Agustin Garcia Reyes, "El Cheje," said the ashes were dumped in eight black trash bags and tossed in a river an hour's drive away.
Authorities have only confirmed the identity of one student among those remains while DNA tests partially identified a second one.