By William Watkinson

A Mexican state human-rights agency has begun an investigation into why as many as 150 bodies of crime victims were dumped into a pit in an area rife with kidnappings and executions. Investigators discovered the bodies, some wrapped in plastic, in unmarked graves in Morelos in central Mexico.

The area has been plagued by violence since the 1990s, when the Juarez Cartel and the Beltran Leyva Cartel began a feud that was further complicated by the emergence of other drug gangs. Several high-ranking Mexico state officials have been accused of aiding traffickers there.

One of the reasons they may have been relocated to the pits might have been to clean out the state morgue, but some of the bodies lack identifying case numbers -- posing questions as to how they met their ends. Other theories allude to haphazard police work or foul play at the behest of narcotics kingpins in the small, indigenous community, infamous for having one of the highest kidnapping rates in the country.

Officials are being investigated for dereliction of duty and violation of laws covering the burial of corpses, prosecutor Javier Perez said in a statement Friday. He did not specify how many officials were being probed or how long the "unauthorized" mass grave in a town east of the city of Cuernavaca is believed to have been in operation.

Investigators visited the town Friday, but the long-running scandal was revealed in 2013 when relatives of a murdered kidnap victim, Oliver Wenceslao, were told that his body had been sent to a mass grave after police officers asked to keep the body for further testing.

A judge ordered the state prosecutor’s office to exhume Wenceslao's body in September of this year and return it to his family. But when investigators began digging, they found as many as 150 bodies in a deep pit.

"The bad thing is that, during this exhumation, they found several things wrong," Rafael Idiaquez, a representative of the state human-rights commission in Morelos, told El Nuevo Herald, a Spanish-language newspaper based in Miami. Ordinarily, Mexican morgues prepare bodies for common graves by placing them in plastic bags.

Within each of these bags is a case file number in an empty plastic bottle to avoid contamination. But Idiaquez indicated at least some of the discovered bodies lacked this crucial information. He said, "There are bodies that don't have any case file number. We don't know why they are there, if they were executed, if they have relatives, if any investigation was ever done in their cases." He added that several people have contacted the commission, saying they fear their relatives may have been buried in the mass grave.

The state prosecutors' office in Morelos claimed that all the corpses had case files in which their fingerprints, dental profiles and genetic profiles were recorded. But it appears the only way to match records would be by using genetic testing on each set of remains.