The death of a Westmoreland County man following an early July arrest on public drunkenness charges is being investigated as a homicide, Allegheny County police said Monday.

West Mifflin Police arrested the 31-year-old man, whom police did not identify, around 3 a.m. July 5 after they responded to a report of an intoxicated man trying to enter a residence near the intersection of Worton Boulevard and Pennsylvania Avenue.

The man was placed in a West Mifflin Police Department holding cell. When officers tried to wake him later, he was unresponsive and taken to an area hospital in critical condition, police said.

On July 8, doctors declared the man brain-dead, prompting West Mifflin police to reach out to county detectives. On July 10, he was pronounced dead.

Through their investigation, county detectives said the man had been in an altercation at a Versailles residence, and was struck in the face. They said the person who struck the man drove him to the Uni-Mart on Worton Boulevard and left him after he regained consciousness.

The Allegheny County Office of the Medical Examiner ruled the death a homicide. County police said it is an active investigation, and anyone with information is asked to call 833-255-8477.

Patrick Varine is a TribLive reporter covering Delmont, Export and Murrysville. He is a Western Pennsylvania native and joined the Trib in 2010 after working as a reporter and editor with the former Dover Post Co. in Delaware. He can be reached at pvarine@triblive.com.