Janesville fire officials are investigating a small fire at a commercial business just south of the city.  Firefighters responded to ABC Seamless in the 2600 block of Highway 51 about 6:30 p.m. Monday.  Officials say the fire was out within 15-minutes.  The Town of Beloit fire Department also responded to assist.  The origin of the fire appears to be a vehicle within the building.  No one was reported injured.