(Quilcene, WA) -- Investigators are trying to determine the cause of a plane crash that killed four people last week near the northern end of Washington's Hood Canal. The victims have been identified as the pilot, 63-year-old Jon Bernhoft of Sequim; his 61-year-old fiancee, Carla Parke; and her two grandchildren, nine-year-old Logan and five-year-old Mackenzie Echevarria of Bellingham. KING-5 reports the single-engine Cessna left Boeing Field for Port Angeles around 6 p.m. Thursday and lost contact with air traffic control around 45 minutes later.