A man with at least four weapons -- including a military-style M4 assault rifle -- is in police custody after he allegedly killed at least one while shooting up a bar in North Fayette, Pennsylvania.

Allegheny County police said that the shooter may have been talking on the phone to his girlfriend at the Fort Pitt Inn before briefly leaving. He later returned to the bar with three weapons and opened fire, according to KDKA.

The station reported that one of the two men who were shot in the neck and head died from his injuries. The other man was at a local hospital in critical condition.

WPXI reported that the dead man had been killed with the M4 assault rifle, while other reports suggested that police found the rifle in the suspect's vehicle after the shooting.

A third man tackled the shooter after being shot in the arm. Bar customers restrained the suspect until police arrived on the scene. In video broadcast by KDKA, the man appeared to be wearing only underwear and had a bloody bandage on his head, presumably the result of a beating at the hands of bar patrons.

After being treated for his injuries, the suspect was taken to the Allegheny County Police Department for questioning. His name had not been released.

Watch this video from KDKA, broadcast March 11, 2013.