Mexico armed forces knew fate of 43 disappeared students from day one

A former Colombian prosecutor, Angela Buitrago, said the group of independent experts found evidence that authorities withheld or falsified evidence from the start of the search.

Buitrago said investigators, prosecutors and military personnel altered crime scenes and records. A government drone video obtained by the experts showed marines and police climbing around the area where the students were allegedly killed with little control.

But the students were under surveillance because their college, which has strong ties to leftwing social movements in Mexico, was viewed as a hotbed of subversion, the experts.

After the abduction, investigators sought to quickly resolve the crime through illegal searches, detentions and torture of suspects.

Mexico has asked the Israeli government to extradite a former top security official, Tomás Zerón, who was the head of the federal investigation agency at the time of the abduction. He is being sought on charges of torture and covering up those disappearances.

The investigation had long been criticized by the families of the 43 students who disappeared in September 2014 after they were detained by local police in Iguala, in Guerrero. They were allegedly handed over to a drug gang and slain, and have not been heard from since.

Many of the suspects arrested in the case were later released, and many claimed they had been tortured by police or the military.