Petaluma police are investigating the case of a drunken man who was punched in the face and had part of his ear bitten off by an unknown assailant near the city’s downtown.

Tipped off by a passerby, officers found the man, who was not identified, bleeding heavily from the ear about 10:30 p.m. Wednesday near Fourth and C streets, Petaluma police said in a news release.

Officers discovered a portion of his ear was missing from the victim, who said he also had been punched in the face.

The man was “acutely intoxicated” and was unable to provide much information about the assault or any potential suspects, the release said. He was taken to Petaluma Valley Hospital for treatment.

Anyone who witnessed the assault should call Petaluma Officer Adam Wirtz at 707-781-1228.