Officer William Morrison was sitting in his cruiser at around 10 a.m. ET Thursday morning at the M&T Bank in Damascus.
Morrison noticed that the teller was behaving strangely and saw the robbery happen.
Morrison pulled around to the front of the bank branch and confronted a suspect as he fled the scene.
The suspect attempted to get into a waiting vehicle, which pulled away without him.
The officer stopped that car and arrested its driver.
The other suspect tried to hide in a wooded are and was taken into custody thanks to searches executed by police from several agencies.
Benjamin Hansberger and John Conley Laforce, both of Frederick, have been charged with robbery.