A $10,000 reward is being offered to help authorities catch and convict a serial bank robber who targeted the Police and Fire Federal Credit Union in the Overbrook Park section of Philadelphia three times in 2013.

Each time, the man presented threatening notes to tellers at the credit union, at 7604 City Ave., and gestured that he has a gun, though no weapon was shown, authorities said.

The last known robbery committed by this man was on Halloween Day 2013. He is also believed to have committed robberies at the branch on two different days in July of that year. In all three cases, he was seen fleeing on foot.

The robber is described as black, in his mid-30s, about 6 foot to 6-foot-2 and of medium build. He sometimes has a scraggly goatee and may also have acne or similar bumps on his face, authorities said. Each time, the man has worn a hat: once, a black Chicago White Sox baseball cap; another time, a black baseball cap with unknown white writing; and one time, a dark-colored flat cap.

Anyone with information is asked to call the FBI at 215-418-4000 or the Philadelphia Police Department. Tipsters can remain anonymous.