L.D. Cooper was a timber faller, or lumberjack for part of his young life, and lived in Sisters, Ore. He served in the Korean War, and was obsessed with the Dan Cooper comics, according to his niece Marla Cooper. The possibility of L.D. being the real hijacker is buttressed by the recollections of Marla and her mother, Grace Hailey.
"I've always had a gut feeling it was L.D.," Hailey told ABC News. "I think it was more what I didn't know is what made me suspicious than what I did know, because whenever the topic came up it immediate got cut off again."
Marla Cooper said that as an 8-year-old she recalled her two uncles planning something suspicious at her grandmother's house in Sisters -- not far from where D.B. Cooper jumped from a plane with $200,000 in cash one day later.
"My two uncles, who I only saw at holiday time, were planning something very mischievous. I was watching them using some very expensive walkie-talkies that they had purchased," she said. She said she now believes the men were practicing for the post-hijacking recovery operation. "They left to supposedly go turkey hunting, and Thanksgiving morning I was waiting for them to return."
A day later, Northwest Orient flight 305 was hijacked, and her uncle L.D. Cooper came home claiming to have been in a car accident.
"My uncle L.D. was wearing a white T-shirt, and he was bloody and bruised and a mess, and I was horrified. I began to cry. My other uncle, who was with L.D., said Marla just shut up and go get your dad," she said.
Marla Cooper is now convinced there was not a car accident, but that her uncle was injured crashing to earth in a parachute. She says that she also remembers a discussion about the money that day.
"I heard my uncle say we did it, our money problems are over, we hijacked an airplane," she said.
It later became clear, however, that there was no money. It is believed that the hijacker lost much of the cash as he came crashing down, and some of the hijacking money was recovered in 1980 when it washed ashore on the banks of the Columbia River.
Marla Cooper said that her two uncles wanted to return to search for the cash, but her father refused. She believes this was because the FBI search was just beginning to take shape.
After that Thanksgiving Day, she only recalls seeing her uncle once more, at Christmas, in 1972, when the picture of him with the guitar strap was taken.
FBI Agent Gutt said the investigation would continue, and would focus on the attempt to find a fingerprint of the late L.D. Cooper to match to the fingerprints the hijacker left on the plane. Without that, the legend of D.B.Cooper may remain a unsolved mystery.