Earl Cossey was found dead in his garage Friday by his daughter, who said she'd been unable to contact her father for several days, Seattle police said.
Investigators combed a wooded area across from Cossey's home for evidence, KOMO-TV, Seattle, reported.
Cossey was working at a local flight school and skydiving operation in 1971 when a Northwest Orient plane traveling from Tacoma, Wash., to Seattle was hijacked by a bomb-carrying suspect who identified himself as D.B. Cooper. The neatly dressed man told a flight attendant he wanted $200,000 ransom along with a parachute waiting for him on the ground in Seattle.
After the plane took off again, ransom in tow, Cooper jumped out, using the parachute Cossey packed -- and was never found.
Police haven't said what they think happened to Cossey or identified any suspects.