A total of 13 bodies have now been found in or around Chapala Lake in western Mexico, an official said Saturday.
The head prosecutor of Jalisco state said that the dead apparently were members of a gang and came from nearby communities. He said they were killed by their former criminal allies in the neighboring state of Michoacán on or around Sept. 21.
The bodies of the 12 men and one woman were then apparently tossed into a river that feeds into the lake. They were found at the opposite end of the lake from the town of Chapala, popular among tourists and American retirees.
Also Saturday, a soldier died in a shootout with criminals in the central state of Guanajuato, one day after five soldiers were killed in an ambush in the northern state of Sinaloa.
The Guanajuato state prosecutor's office said police and soldiers were chasing a three-vehicle convoy of armed men in the township of Comonfort, Guanajuato, when the gunfight broke out and the soldiers was shot to death.
It appeared unrelated to Friday's attack on a military convoy in Sinaloa, which was likely launched to free a wounded drug suspect being transported in an ambulance guarded by the convoy.
In a speech Saturday, Defense Secretary Gen. Salvador Cienfuegos used unusually harsh language to describe the attackers, who apparently used grenades to attack the army convoy.
"Our soldiers were ambushed by sick, insane criminal beasts," Cienfuegos said.