The four bodies were bound hand and foot and dumped near an old tin mine. Two had been doused with powdered quicklime, and two were identified as people who had been reported missing between May and June.
In a more remote area nearby, inspectors found the remains of nine men and one woman scattered in the brush. All had been covered with quicklime. Some of the bodies were also bound, and experts said they had apparently been dumped there about a month ago. About two dozen spent .380-caliber shell casings were found at the scene.
Drug cartels frequently use quicklime to hide the scent of decomposing bodies and help them decay faster. The area, near the border with neighboring Guanajuato state, has been the scene of bloody turf battles between the Jalisco cartel and another gang.