A group of armed men stormed into a bar in western Mexico and threw five human heads on the floor in an incident apparently linked to illegal drug trafficking.
Witnesses say the 20 men fired shots in the air as they entered the bar in Michoacan state before dawn Wednesday.
The group also left a note saying the killings were part of what it called "divine justice."
Officials say relatives of three of the victims had identified their bodies and claimed they were not connected to illegal drug gangs.
Mexican police have found several victims from similar attacks earlier this year.
Mexico's President-elect Felipe Calderon has vowed to crack down on violent crime when he takes office in December.