The investigation into the murder of a mayor in central Mexico has led police to a clandestine grave containing five other bodies, authorities said on Tuesday.

The burial spot was found in the community of Alpuyeca following the killing of Temixco Mayor Gisela Mota, who was murdered on Saturday, just one day after taking office.

"As a result of this regrettable event in Temixco, an investigative process was triggered that led us to make another discovery," said Matias Quiroz Medina, a senior Morelos state government official.

Three people - a 32-year-old woman, an 18-year-old man and a 17-year-old boy - who were detained right after the mayor's murder were formally charged with homicide on Tuesday. Two others were killed in a shootout with police on Saturday. Officials did not say whether the grave had any direct links to Mota's murder.

Authorities suspect that the drug gang known as Los Rojos killed Mota, 33, because she backed a plan to place state and municipal police into a unified command structure.

UN agencies for human and women's rights condemned Mota's killing.