State police cannot determine a single cause of a fire that destroyed a home in Middlesex Township on Feb. 9. State police fire marshall Jeff Crede said on Thursday the home, at 420 W. Cruikshank Road, was too extensively damaged to enter safely for an investigation. He said the floor and ceiling were burned and a wall was buckling at the scene, which prevented investigators from entering the home. Crede said homeowner Joe Jansen told him he saw chest-high flames on the computer desk in the great room in the front of the home. Firefighters from a half dozen companies fought the blaze. Damage to the home that Jansen and his wife, Linda, have owned since it was built in 1979, was estimated at about $200,000