SHEBOYGAN, WI (WHBL) - The Sheboygan and Fond du Lac County Sheriff's Departments have joined forces in investigating three recent armed robberies, which may be related. Captain Dave Adams, of the Sheboygan County Sheriff's Department, said both departments are working on the cases, since they appear to be related. Two occurred in Sheboygan County just over a week ago - one in Random Lake on Friday, March 8th, the other in the village of Cascade on Sunday, March 10th. Then, over the weekend, someone robbed a food mart on Highway 45 in the town of Osceola in Fond du Lac County. In all three cases, the robber displayed a handgun and left with an undisclosed amount of cash.