It happened Monday at 12:20 p.m.
Investigators say the man walked into the Republic Bank branch at 1818 Market Street, showed the teller a demand note and fled on foot, heading west on Market Street with an undisclosed amount of cash.
Police released the following description of the suspect:
Black male, 30-40 years old, 6'0?, slender build, scruffy facial hair, wearing a dark knit cap, black coat, blue jeans, sunglasses and light brown boots.
Anyone with information about the crime or suspect is asked to contact the FBI/PPD Violent Crimes Task Force at 215-418-4000.