About 600 people were at the "Philly Support Philly: Peace on the Streets" concert Wednesday night in the Strawberry Mansion Center when gunfire broke out in the parking lot at 8:30 p.m. Witnesses said two young men got into an argument and one pulled out a gun.
The 20-year-old victim was wounded in the stomach and thigh. He died overnight at Temple University Hospital.
The gunman drove off in a white car that witnesses said might have been a Chevrolet Impala.
This summer has been marked by high-profile killings in Philadelphia. They include a young girl who was hit by a stray bullet as she got her hair braided on a neighbor's porch and the deaths of a woman and her three children struck by a carjacked SUV as they sold fruit for a church project.