Hagerstown Police and K-9 units were on the scene, after an AC&T employee sounded the panic alarm around 8:30pm.
Police say the suspect is reported to be a white male who was wearing all-dark clothing, a mask and gloves. They say he made off with an undisclosed amount of cash and did not show any weapon.
Police say they continue to up their patrol in this area, including surveillance cameras.
"What I can say for certain is that after this evening, patrols are going to be upped, and a bunch of other investigative procedures and techniques will be undertaken, in order to prevent future occurrence at this business," says Sergeant John Lehman, with Hagerstown Police Department.
Police have not made a single arrest in relation to any of these recent robberies, and are still investigating whether or not they are related. All three culprits have stolen undisclosed amounts of money in the last three robberies.