A woman in the United States is claiming that her uncle carried out the brazen hijacking of an airplane 40 years ago and escaped with $200,000 in the only unsolved skyjacking in American history.

Marla Cooper told the ABC News television network that she is convinced the 1971 hijacking was carried out by her uncle, a man she identified as Lynn Doyle Cooper. He is believed to have died in 1999.

The mystery surrounding the hijacking over the northwestern states of Oregon and Washington has fascinated Americans for four decades. Law enforcement officials have tracked down hundreds of leads in the case but have not been able to figure out who the hijacker was.

The hijacker came to be known in U.S. lore as D.B. Cooper, although he gave his name as Dan Cooper on the hijacked flight. The hijacker claimed to have a bomb after the plane took off from Portland, Oregon, and demanded to be flown a short distance to Seattle, Washington. He let passengers off the plane in Seattle in exchange for parachutes and the ransom money.

The plane then took off for Mexico, and the hijacker parachuted out the plane's rear door with the money into the rugged forests of the Pacific Northwest, never to be found.

But Marla Cooper said in the television interview that she remembers seeing her uncle “bloody and bruised and a mess” that Thanksgiving holiday, claiming to have been in a car accident. But she recalled him saying: “We did it, our money problems are over, we hijacked an airplane.”

She said she never saw him again.

The woman said she gave the U.S. Federal Bureau of Investigation a guitar strap and a photo of her uncle that could help it determine whether the long-ago mystery can at last be solved. The FBI said Monday it was pursuing a new lead in the case.