State police found the four bodies in the community of Rincon de la Via after receiving a call from a local police precinct chief about a shootout, Efe quoted state security spokesman Roberto Alvarez as saying.
Antonio de Dios Navarrete, the 32-year-old commander of the UPOEG community self-defense group, died in the shootout.
UPOEG, whose members are armed, was created in January 2013 in the cities of Ayutla de los Libres, Teconoapa and San Marcos to protect residents.
The self-defense group controls access to communities and polices them to fight drug traffickers and other criminals.
Investigators found numerous 7.62-mm and .223-caliber bullet casings in the community, as well as the vehicle, which was riddled with bullet holes.
About 70 Rincon de la Via residents set up checkpoints to force the UPOEG to leave the community, and they demanded the release of several people kidnapped on Sunday, the state security spokesman said.
Residents of the communities of Buena Vista de la Salud and Ocotito, meanwhile, said three people were wounded in an attack and taken to the General Hospital in Chilpancingo, the capital of Guerrero.
Residents said members of the Los Ardillos gang killed the four men found in Rincon de la Via and shot the three people in the other communities, Alvarez said.
The UPOEG and FUSTEG vigilante groups, which are battling each other, as well as gangs, such as Los Ardillos, operate in this part of Guerrero, the state security spokesman said.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
