The airplane sustained substantial damage on impact with a roadway embankment following a reported loss of engine power while on approach to land. Night visual conditions prevailed. A rear-seat passenger sustained minor injuries. Both occupants of the front seats were seriously injured; they subsequently died as a result of their injuries. The rear-seat passenger subsequently stated that the pilot said that the airplane lost engine power. She stated that the airplane was in a turn while on approach during the reported engine power loss. The left and right tip tanks exhibited tears in their fiberglass construction. The left and right auxiliary fuel tanks contained a fluid that exhibited a smell consistent with aviation gasoline (avgas). The left and right main fuel tanks did not contain any fluids. The smell of fuel was present at the accident site. The fuel tank selector was found in the detent selecting the left main tank. When the fuel selector was rotated to the detent for the auxiliary tank and battery power was applied to the electric fuel pump, a fluid consistent with avgas was observed exiting from the supply line to the engine driven fuel pump.