It happened around 10:30 p.m. on Thursday.
Police found a man in his late teens to early twenties shot in the head outside the Shops of Wissinoming at Harbison Avenue and Tulip Street.
"Preliminary information is this homicide victim showed up in the parking lot with one other male, and was meeting two or three other males in the parking lot. And that's when we know guns were drawn, by not only the victim of the homicide but the shooter. There was some sort of shootout," said Chief Inspector Scott Small with the Philadelphia Police Department.
The other shooter remained on scene.
Police say that person and witnesses are cooperating.
Investigators do not know what set off the gun violence.
RELATED: Check the 6abc Neighborhood Safety Tracker