Authorities are investigating a mass grave in southern Mexico containing 167 bodies that may have been dumped there at least 50 years ago, a Mexican official said on Saturday.
The remains, found in a cave near the Guatemalan border, "disintegrated at the touch," said the official at the Chiapas state prosecutor's office.
Investigators are trying to determine the age and gender of the victims and the cause of death, the official said on condition of anonymity.
The advanced state of decomposition suggests they are at least 50 years old, he said, adding there were no obvious signs of violence.
Mexican authorities including the police, the prosecutor's office, civil protection personnel and the military were working to exhume the bodies and transport them for analysis.
The grave is on a remote ranch near the town of Frontera Comalapa, about 11 miles (18 km) from the Guatemalan border in an area where migrants from Central America often cross on their way to the United States.
A 36-year civil war in Guatemala, which began in 1960, claimed 250,000 lives and left 45,000 people missing. Activists suspect they were killed by soldiers and secretly buried.
In recent years, drug trafficking gangs have dumped the bodies of hundreds of victims, including scores of Central American migrants, into mass graves.
