The FBI’s “promising lead” on the D.B. Cooper case has been revealed: A woman named Marla Cooper recently contacted the agency to say that her deceased uncle, Lynn Davis Cooper, was the famous criminal who hijacked a plane and parachuted to safety. "I'm certain he was my uncle, Lynn Doyle Cooper, who we called L.D. Cooper,” Marla told ABC News. She says she remembers as an 8-year-old watching her two uncles planning “something very mischievous” at her grandmother’s house in Sisters, Ore., during the 1971 Thanksgiving holiday. The uncles disappeared; the hijacking occurred; and L.D. returned the next day, “bloody and bruised and a mess,” saying he had been in a car accident. Marla has provided the FBI with a guitar strap for fingerprints and also photos of L.D., who died in 1999.