MEXICO CITY -- Authorities in southern Mexico have found the severed heads of six men in a plastic bag on the roof of a sport utility vehicle, and six headless bodies inside.

The security spokesman for the southern state of Guerrero said the bodies were found Monday in Chilpancingo, the state capital.

Roberto Alvarez said four more bodies were found in the nearby township of Chilapa.

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Of those four, two were found shot to death on a highway and had apparently been tortured. The other two bodies were found inside a house in Chilapa and also bore signs of torture.

The area has been the scene of bloody turf battles between rival drug gangs.