There is newfound media interest in the D.B. Cooper case as the FBI follow a "promising" lead to solve the 40-year mystery of the hijacker's true identity once and for all.

On November 24, 1971, a 6 ft. man in sunglasses and dark suit boarded a Northwest Airlines flight headed from Portland to Seattle. After ordering whisky and lighting a cigarette (which was allowed back then), he sent a letter to a flight attendant: 'I HAVE A BOMB IN MY BRIEFCASE. I WILL USE IT IF NECESSARY. I WANT YOU TO SIT NEXT TO ME. YOU ARE BING HIJACKED.'

He then received $200,000 and parachutes from feds in exchange for passengers after a brief landing, demanded to be flown from Seattle to Mexico at low altitude, and jumped out of the plane's tail exit. The hijacker was never seen again.

Recently, a woman named Marla Cooper emerged to reveal what she claims is a 40-year-old family secret of her uncle, Lynn Doyle Cooper. She claims he is the notorious hijacker that stumped authorities for decades, and DNA tests of a guitar strap he owned are now under way to confirm if it matches up with a tie-pin left behind in the plane. The feds are closer to solving the hijacker's identify, if this Lynn Doyle Cooper indeed is, D.B. Cooper.

The woman was just eight at the time, but remembers her uncle planning something "mischievous" and suspicious the day before, and left with another uncle to go "turkey hunting". Lynn Doyle returned triumphant but injured the next day, with a bloodied white shirt, and told the family they were now rich. The family then danced in their garden to celebrate.

"I contacted the FBI as soon as I was sure that what I was remembering were real memories," she told ABC. "There's a crime that's taken place that hasn't been solved and I'm the only one, as far as I know, who knows what happened.

"We called him L.D. Cooper." The niece said her uncle was obsessed with comic book hero Dan Cooper, which could be where he got his pseudonym.

"I heard my uncle say we did it, our money problems are over, we hijacked an aeroplane," she told ABC.

The family kept the story secret for years, but just before Marla's father died in 1995, she recalls him commenting on his long lost brother. "'Don't you remember he hijacked that aeroplane?'"

Although Marla Cooper never saw her uncle again since that day, she was told he lived on until his death in 1999.