Officers responded to the store on the 4900 block of North Broad Street near West Ruscomb Street around 10 a.m. Monday.
Inside, they found an adult male suffering from gunshot wounds.
He was transported to Einstein Medical Center and pronounced dead a short time later.
The victim's role in the violence is still unclear.
So far, no arrests have been made, and no weapons have been recovered.
The shooting remains under investigation.