Two men shot to death in Nogales, Sonora were Arizona residents, the Mexican state police reported Monday.

Family members identified the men as Antonio Miguel Coronado Corral, 22, and Adrián Alejandro Coronado Corral, 20. The brothers lived in the city of Maricopa. Arizona State Police officials said the men were U.S. citizens.

About 1 p.m. Sunday, officers responded to reports of gunshots in the Chula Vista neighborhood, close to the downtown area in the northern part of the city. Officers arrived to find the bodies and handgun shell casings at the crime scene, an agency news release said.

Two cars there, a black Dodge Charger with Arizona license plates and a white Buick sedan with Sonora plates, had collided head-on, the release said. Officers found the body of Antonio Miguel Coronado Corral about three feet west of the Buick, his brother’s body was lying in between both cars.

The investigation is ongoing.

This story was updated at 12:40 p.m. on March 18, 2014. Officials said the men were U.S. citizens.