Station 3 responded mutual aid to Mount Airy this morning for the working house fire. At 0818 the station was dispatched to the 2800 block of Flag Marsh Road after units from Carroll County's Mount Airy Volunteer Fire Company found a two story A-frame type home with heavy fire showing. First-in crews located an elderly female inside the home who was deceased. Crews from Station 3, among other things, set up a secondary water source using Water Supply 3 at Newport Road and the county line. Units remained on scene until well into the afternoon conducting salvage and overhaul as well as assisting the Maryland State Fire Marshal's Office, who said the fire started in the living room of the home. No cause has been determined.