Authorities in north Mississippi are searching for a group of serial, armed robbers that have hit six Dollar General stores over the last three months, a Memphis TV station reported Monday.

Stores in Attala, Benton, Marshall and Panola counties have been robbed, WREG in Memphis reported.

In each robbery, three thieves came into the stores just before closing time, brandishing guns and wearing masks over their faces, sheriff’s office investigators reported.

In each case, they fired their guns as they demanded cash, but didn’t aim at anyone, apparently, as no one has been injured.

One witness said the gunmen ran into the store and began screaming, “Open the drawer or I’m going to shoot”

Anyone with information about the crimes is asked to contact the Marshall County Sheriff’s Office at (662)-252-1311.