Mexico City - Authorities in the northern Mexico border state of Sonora have found eight bodies in two clandestine burial pits.
Sonora state police say they were acting on a tip when they found the pits along a dirt road near the city of Navojoa.
The bodies found on Sunday include six men, one woman and a girl. Investigators say they may have died as long as a year and a half ago.
The causes of deaths are being investigated.
Drug cartels in Mexico frequently use such pits to bury executed rivals.
Twenty bodies so far have been excavated from eight clandestine graves found last week in the western state of Jalisco.
The area is the site of a turf war between the Knights Templar and the New Generation cartels.