OKLAHOMA CITY (AP) — When an FBI agent pleaded several years ago for help finding notorious skyjacker D.B. Cooper, he wondered, off-handedly, if someone's "odd uncle" might be their guy.
Marla Cooper believes that her late uncle Lynn Doyle Cooper was the man who hijacked a plane in 1971 and parachuted away with $200,000 ransom into a rainy night over the Pacific Northwest.
The FBI has for years tried to find out if D.B. Cooper survived the jump, chasing more than 1,000 leads as the man who pulled off the nation's only unsolved hijacking became part of American folklore.
The agency said it is following up on a "credible" new lead in the Cooper case. FBI agent Fred Gutt declined Wednesday, however, to say whether Marla Cooper was connected to that lead.
"It is an unsolved crime and we are obligated to address that if new, credible information comes to us," he said, adding that the case is a low priority. The FBI is focused on criminal activity that threatens communities today, he said.
Marla Cooper told ABC News, which first reported her comments in an interview broadcast Wednesday, that she made the connection by piecing together her memories and her parents' comments over the years. Cooper, however, did not say why she chose to speak out now.
Cooper claimed on "Good Morning America" that she heard her uncle, L.D. Cooper, and another uncle planning something "very mischievous" over the holidays in 1971. "I was watching them using some very expensive walkie-talkies that they had purchased," she said.
Marla Cooper said her uncles said they were going turkey hunting around Thanksgiving.
On Nov. 24, 1971, a man who gave his name as Dan Cooper claimed shortly after takeoff in Portland, Ore., that he had a bomb, leading the flight crew of the Northwest Orient plane to land in Seattle. Passengers were exchanged for parachutes and ransom money.
The flight then took off for Mexico with the suspect and flight crew on board. The hijacker parachuted from the plane after dark as it flew south, apparently over a rugged, wooded region not far from Marla Cooper's grandmother's home in Sisters, Ore.
Marla Cooper said her uncle, L.D. Cooper, came home claiming he had 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 said she heard her uncle say at the time, "We did it. Our money problems are over. We hijacked an airplane.'"
She said that, just before he died in 1995, her father mentioned his brother and said, "'Don't you remember he hijacked that airplane?'" In 2009, she said, her mother made a similar comment that raised her suspicions again.
Cooper said she contacted the FBI "as soon as I was sure that what I was remembering were real memories."
Seattle-based FBI case agent Larry Carr was tasked with reigniting the case five years ago and the agency posted a "D.B. Cooper Redux" on its site in 2007, urging the public to help solve the enduring mystery.
The FBI released photos of a black J.C. Penney tie the hijacker wore and some of the stolen $20 bills found by a young boy in 1980 along the banks of the Columbia River.
In the FBI's recounting of the case, it quoted Carr as saying he thought it was likely that Cooper didn't survive the jump, but he still sought the public's help.
"Maybe a hydrologist can use the latest technology to trace the $5,800 in ransom money found in 1980 to where Cooper landed upstream," Carr said. "Or maybe someone just remembers that odd uncle."
The FBI said Monday that a new lead came to the bureau after the tipster initially discussed the case with a retired law enforcement officer, who then contacted the agency.
Gutt said only after the FBI contacted the tipster directly did the person speak with investigators.
The lead focuses on a suspect who died more than 10 years ago.
Marla Cooper did not discuss on ABC how or when she reached out to the FBI, but said she recently provided investigators with a guitar strap belonging to her uncle to be tested for fingerprints.
Investigators have tested a guitar strap from the suspect who is the subject of the new lead, Gutt said Wednesday, but found it wasn't suitable for fingerprint analysis.
They are now working with family members to identify other items that can be analyzed.
But the FBI doesn't have a timeframe for how long it will take to vet the lead, which is something they've known about for more than a year, Gutt said.
Associated Press writer Mike Baker in Olympia, Wash., contributed to this report.
Copyright 2011 The Associated Press.