It happened at 6:15 a.m. Saturday at the Friendly's restaurant in the Andorra Shopping Center in the 9100 block of Ridge Avenue.
Police say a gunman followed an employee into the restaurant, forced all the employees into a supply closet, then stole an undetermined amount of cash.
He then fled the scene, possibly in an older dark green minivan.
Police have released the following description of the suspect:
Black male, 6'1" tall, 160lbs, 30 years old, with a beard and medium complexion. He was wearing a black skull cap, black hooded sweatshirt, black jeans, white gloves and brown boots.
Anyone with information about the crime or suspect is asked to call Detective Cannon at the Philadelphia Police Northwest Detective Division, 215-686-3353/3354.