Mansfield Fire Department responded to a call of a fully involved structure fire on Penn Ave. The fire was located in the garage located at the rear. The dispatcher advised that there may be a man in the garage. A firefighter on the scene confirmed no one was found in the garage.  Mansfield Police were also called to the scene. Scanner traffic reported someone was seen running from the scene. The cause of the fire is unknown. Scanner traffic did report it may be arson.