It happened on February 24.
Surveillance video shows the 38-year-old male victim was making a deposit at an ATM at the Wells Fargo Bank on the 700 block of Adams Avenue shortly after 9 p.m.
As the man turned around, the robber approached him from behind, pulled a handgun from his waist and demanded cash.
The victim stated he didn't have any money, so the robber then demanded his ATM card instead.
After getting the card but realizing the victim gave him the wrong PIN number, the suspect then fled on foot.
He was last seen in the area of Tabor Road and Foulkrod Street.
Police describe the suspect as a black male, 16-18 years old and 6'0" tall with a thin build. He was wearing a black hooded jacket, tan pants, white shoes and armed with a handgun.
If you recognize this man, call police at 215.686.TIPS (8477) or text a tip to PPD TIP (773847).