At least 55 bodies have been recovered from an abandoned silver mine which became a dumping ground for apparent victims of drug violence.
Albertico Guinto, attorney general for the state of Guerrero, said the overall toll could still rise at the mine on the outskirts of Taxco, a colonial-era tourist town famous for its silver jewellery. Forensic examiners were trying to determine whether other human remains, clothing and shoes found in the nearly 150m-deep shaft correspond to victims already included in the tally, he said.
Most of the bodies have not been identified, but prosecutors said one was a prison director who had been kidnapped. At least 15 people have been detained in the case.
Police discovered the mass grave following a tip-off after the arrest of an organised crime suspect in Iguala.
Meanwhile, authorities in the Caribbean resort of Cancun were working to identify six bodies found in a cave over the weekend.
Francisco Alor, the attorney general for Quintana Roo state, said after the bodies were found that three had been cut open and their hearts removed. He retracted that statement the next day, saying autopsies showed the organs were stabbed multiple times and essentially destroyed, but were never removed.
Drug gang violence has claimed more than 22,700 lives since President Felipe Calderon launched a crackdown on cartels shortly after he took office in late 2006.