The Maine fire marshal’s office is investigating a fatal fire at a mobile home in Presque Isle that was discovered at about 4:30 a.m. Sunday. Officials said a body found inside the burned-out home is believed to be Shawn Whitington, 36, who lived there with his girlfriend, Tricia Ciccolella, and their 4-year-old daughter. Authorities said Ciccolella and the child were not at home when the fire broke out. Ciccolella discovered the fire when she returned home with friends, but smoke and flames prevented them from getting into the mobile home. The cause of the fire has not been determined.