"The victim evidently is just an innocent guy who got caught up in this tragedy," said Chitwood, adding that Campbell had no criminal record.
Campbell suffered gunshot wounds to the left side of his head and chin, and died at the Hospital of the University of Pennsylvania.
At least a dozen casings were found at the scene, Chitwood said.
When police arrived, about 200 people had spilled out of the bar, in a one-story building on Garrett Road along a commercial strip near the 69th Street Terminal, and into the public parking area across the street.
Police were able to interview witnesses, and also talked to the owner after he emerged from the club at 6:15 a.m.
"We have a pretty good idea who did it," said Chitwood. No arrest had been made as of late Monday, and the investigation was continuing.
The Venue, which recently operated under the names Traxx and Rhythms - and still bears the Rhythms name in a sign above the door - has been on the police radar for three years, Chitwood said.
It is one of five locations in the township that have been the scenes of fights, drug activities, and shootings, he added.
He said police have a "three-inch file" on the club chronicling alleged misconduct.
"We've been trying to shut it down," he said, "because it's a real nuisance."
Contact staff writer Anthony R. Wood at 610-313-8210 or firstname.lastname@example.org.