(Murphysboro, IL)– Murphysboro Police are investigating an armed robbery that happened in the early morning hours August 5th, at Motomart, located at 110 S. Williams St.  Police say shortly before 4 a.m., the suspect, a single black man, walked into the store wearing a mask. He displayed a knife and demanded money. The clerk gave the suspect an undetermined amount of cash. The suspect then ran south from the store. Police say more details are possible as the investigation continues. If you have any information, you should call Murphysboro Police.