As soon as witnesses inside the bank saw the suspect, described as a tall black man, wearing the mask, they called 911, police said.
He fled the bank with a wad of money in his hand, but dropped it.
Law enforcement officers from the Jefferson County Sheriff’s Office, Louisville Police Department and the Georgia Bureau of Investigation are coordinating efforts to identify and capture the robber.
Jefferson County Sheriff Gary Hutchins said the man left the bank property in a white Ford Explorer. Officers have not disclosed the amount of money taken or whether it was all recovered when it was dropped.
No one was injured during the robbery, according to an officer on the scene.