O’FALLON, Ill. (KMOX) – A woman was so calm and quiet in robbing a Metro-East fast food restaurant early Tuesday morning, that the customer eating breakfast didn’t even know the place was being held-up.

O’Fallon Police Lt. Mick Hunter tells KMOX the suspect entered the Hardee’s on Highway 50 at Parkview Drive at 5:45 a.m., with a scarf over her face and a semi automatic handgun in her hand.

“She basically just walked in, walked behind the counter and calmly asked the employees, at gunpoint, to empty registers within the store,”Lt. Hunter said.

Hunter says the suspect knew the store’s layout so well that they think she may work, or has worked, at a Hardee’s.