A sucker punch allegedly delivered by Westville’s Matthew Shields at a Jimmy Buffet concert Tuesday night has left a 20-year-old in critical condition.

Authorities say Shields, 21, approached the unnamed victim from behind and punched him in the head during the concert at the Susquehanna Bank Center in Camden on Aug. 28. The victim, who lives in Bellmawr, fell and struck his head against the pavement, according to the Camden County Prosecutor’s Office.

Shields and the victim know each other, authorities say.

Shields turned himself in to the Westville Police Wednesday morning as a warrant was being issued for his arrest. He was charged with aggravated assault and held in the Camden County Jail on $50,000 bail.

The fight happened in parking lot nine, and authorities want to speak to anyone who witnessed the events. Witness may contact Camden Police Det. Kevin Lutz at 856-655-4750.