One suspect made a deathbed confession that he was the never-captured skyjacker D.B. Cooper. Another was a fugitive at the time of the hijacking. Still another was an airline worker and former paratrooper.
Each had a face that closely resembled Cooper's. None were him.
For nearly 40 years, the FBI has chased the ghost of the man responsible for the nation's only unsolved hijacking, with each exhausted lead growing his stature in American folklore.
The latest example to pique public fascination _ and FBI interest _ is an Oklahoma woman who claims her uncle was the man who parachuted out of a plane in 1971 with a $200,000 ransom. Piecing together memories from when she was 8 years old and comments her parents made in recent years, Marla Cooper said she is certain that the legendary D.B. Cooper is actually Lynn Doyle Cooper.
She said her uncle arrived at the family home in Oregon, bloodied and bruised, shortly after the hijacking of the Northwest Orient airliner. She said she overheard her uncles talking about having hijacked a plane.
The FBI agent assigned to the case before his retirement in 1980 is skeptical. Ralph Himmelsbach is no longer involved in any part of the Cooper investigation but recalled chasing hundreds of potential suspects over the years.
"To date, none of them has panned out," he said.
"We still do not know who is, or was, or where he came from, or where he went," he said. "This is still a mystery."
What investigators do know is that on Nov. 24, 1971, a man in his mid-40s and wearing dark sunglasses boarded a Boeing 727 at Portland International Airport. With a ticket under the name Dan Cooper, he took seat 18F, ordered a bourbon and water.
Then he handed a flight attendant a note: "Miss, I've got a bomb, come sit next to me _ you're being hijacked."
Cooper (a law enforcement official later erroneously referred to him as "D.B." and the initials stuck) opened a briefcase that appeared to contain explosives and demanded $200,000 and parachutes. Officials met his demands when the plane landed at Seattle-Tacoma International Airport, where passengers and two flight attendants were released.
The man in 18F then ordered the flight crew to take the plane back into the air, insisting that it fly at an altitude of no more than 10,000 feet on its way to Mexico through Reno, Nevada.
About 40 minutes after takeoff, a signal light in the cockpit showed that the plane's rear stairway had been extended. When the jet landed in Reno, the stairs were down and two parachutes, the money and Cooper were gone.
Himmelsbach has long theorized that Cooper didn't survive the jump into the frigid air and rugged terrain around the Washington-Oregon border. A child digging in a sand bar on the north bank of the Columbia River west of Vancouver found a bundle of $20 bills in 1980 that had serial numbers matching some of the ransom money.
There's been no other sign of where Cooper went.
The latest tip is just one of several that the FBI considers an active lead. It's also the latest in a long line of leads that seemed to hold promise for investigators.
There was John List, a fugitive accused of killing his family in New Jersey days before the hijacking.
There was Duane Weber, who had served prison time near Seattle and told his wife in a 1995 deathbed confession that he was Cooper.
There was Kenneth Christiansan, a former paratrooper and an employee of the airline operating the hijacked plane.
There have been bold claims and copycats but still no sign of the real D.B. Cooper.
A few years ago, the FBI renewed its push to solve the case, releasing photos and new case details in the hopes of jogging memories or prompting someone to come forward. Seattle-based FBI case agent Larry Carr provided at the time a comment that could turn out to be prophetic.
"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."
Marla Cooper said she never gave much thought to what she saw in 1971 until comments from her father before his death in 1995 and her mother two years ago. She then looked up the story of D.B. Cooper and was flooded with the memories of what happened.
She said her uncle died in 1999.
Investigators do have fingerprints from an in-flight magazine and DNA from the black tie that Cooper wore before he jumped. Recently, they tested a guitar strap previously owned by the new Cooper suspect but found it wasn't suitable for fingerprint analysis.
Officials are now working with family members to gather other items on which Cooper may have left prints but they caution that the latest is just one of several leads and remains a low priority amid other FBI duties.
Over the years, Cooper's disappearance has spawned an entire subculture of amateur sleuths, conspiracy theories and celebrations.
In a new book to be released next week, Geoff Gray documents the quests of people who have devoted their entire lives to unmasking Cooper's identity. Gray said Cooper draws so much interest because he quickly emerged as a sort of Robin Hood-type figure who was willing to commit the most dramatic of crimes.
"By falling out of that plane _ either to his death or his life _ he shifted the moral landscape of the country for that moment," Gray said. "He makes the good guys root for the bad guys."
Associated Press writer Mike Baker can be reached at http://twitter.com/MikeBakerAP