METHUEN, Mass. (WHDH) -- Police are investigating a break-in at a local fast food restaurant early Thursday morning.

Police said the suspects were on foot and were able to get in the drive-through window because it was unlocked. Officials said the suspects reached in and opened the locked register by entering a fake order and then pressed the cash button.

Investigators said the register opened and they took off with the cash drawer.

Employees were in the restaurant when the incident happened. The general manager said the manager on duty at the time will likely be fired because protocols were not being followed. He says the drive-through window should have been locked. The general manager added that he wouldn’t be surprised if this was an inside job or if an angry former employee was behind the theft.

Police found the nearly-empty cash drawer behind a nearby gas station. No arrests have been made.