Charles County police said at week's end they are still searching for a suspect in connection with a series of robberies they believe to be related, each committed by an armed man wearing a gas mask.

The latest robbery occurred just after midnight on Thursday at the Dash-In in the 2000 block of Smallwood Drive in Waldorf. The robber, wearing a gas mask and a blue shirt, entered the store with a handgun and demanded money. He took money and cigarettes, then fled, according to Craig Renner, spokesman for the Charles County sheriff's office.

Similar robberies have taken place in Waldorf at the St. Charles Quick Shop, Texaco/Dunkin Donuts, the Waldorf Motel and McDonald's. No one has been injured during the robberies. Police said the hold-ups could involve more than one robber.

Police describe the male suspect as between 5 feet 8 inches and 5 feet 10 inches tall and weighing about 150 pounds, with dark, curly hair. In each incident, the robber wore a black gas mask and sometimes a hooded sweat shirt and jeans.

People with information about the robberies can call the Charles County sheriff's office at 301-932-7777.