Hagerstown Police are trying to identify a man who robbed someone on Concord Street early Thursday morning.

Around 4:30 a.m., a man displayed a knife and took a set of keys and a car from the victim. The victim called police with a description of the man who was found on West Washington Street and arrested a short time later.

The victim positively identified the suspect. The stolen vehicle has not been recovered yet. Anyone with information is asked to the police.