Butler Township police are investigating a suspected assault Monday night in the parking lot of a bar that left a 28-year-old man in need of treatment at a Pittsburgh hospital.

The victim suffered injuries that included a black eye, a cut to the back of the head and a small puncture wound in his back that may have been inflicted by an object other than a knife, police Lt. Matthew Pearson said Tuesday.

The man was flown by medical helicopter to UPMC Presbyterian hospital, where he was treated and released only a few hours after the assault outside Rock Ann Haven on Greenwood Drive.

Police did not release the victim's name. Pearson said they have no suspects and the investigation is ongoing.

Authorities were called shortly after 10:10 p.m. for the reported assault. Police briefly spoke to the victim before he was taken to Moraine Pointe Plaza, where he was air lifted to the hospital with his injuries.

Police said the victim had been a customer at the bar before the incident. He was with at least two friends at the time. Investigators have spoken to the friends, who saw the assault.

Pearson said police have not spoken to the victim since he was released from the hospital, but they were expecting to interview him Tuesday. He has no known address, police noted.

Investigators are “exploring multiple motives” for the assault, Pearson said.

Police also are investigating if there is surveillance video of the incident.