Police in Mexico's Guerrero state are investigating the killings of five men found decapitated near the resort town of Acapulco, authorities said Saturday.

The men were between 20 and 30 years old and were found in a car in the region of Costa Grande in the subdivision of Tamarindo, less than 3 miles from Acapulco, Guerrero state police officer Jorge Tellez told CNN.

All five showed signs of torture and their bodies were riddled with bullets, police said.

Three of the men were killed Friday, investigators said. They did not know when the other two died.

All were Mexicans, according to Guerrero state public security and civil protection spokesman Arturo Cuellas.

Three of the victims were identified as Jonathan Gomez Tellez, Jose Pastor Valencia and Osiris Villanueva Vargas. Police are working to determine the identities of the two others.

Guerrero state police said they did not know the motive of the killings.

Guerrero is in southern Mexico and is contentious territory for drug cartels. The state is near a major drug trafficking artery for such drugs as cocaine, which flow through Central America from Peru and Colombia.