Police say the subject has targeted the Police and Fire Federal Credit Union branch at 7604 City Avenue in the Overbrook Park section of the city multiple times.
Each time, he presents a threatening demand note to tellers and gestures that he has a gun, but no weapon has been physically displayed.
The most recent incident took place on October 31st, where the suspect ended up fleeing the credit union empty-handed.
He is also believed to be responsible for robberies at Police and Fire Federal Credit Union branch on July 1, 2013 and July 29, 2013, in which he obtained undisclosed amounts of cash and fled on foot.
The subject is described as a black male in his mid-30s, approximately 6'-6'2" tall, medium build, scraggly goatee, medium to dark complexion, and he may have acne or similar bumps on his face.
Police say the suspect has worn a hat in each robbery, including: a black baseball cap with unknown white writing; a dark-colored flat cap; and a black Chicago White Sox baseball cap with white "Sox" lettering.
He is considered armed and dangerous.
Police are asking anyone with information about these robberies to call the FBI at 215-418-4000 or the Philadelphia Police Department.
The Police and Fire Federal Credit Union is offering a reward of $5,000 for information leading to an arrest and conviction. There may also be an additional reward from law enforcement.