DB Cooper was the name given by the FBI to the mystery man behind the famous plane hijacking in 1971.
His identity appears to have remained a mystery until now, with a new book stating it has revealed the culprit of the event 46 years ago.
The man is thought to be Walter R Reca, an ex-military paratrooper who managed to escape with the money and his life.
The book, written by his self-proclaimed best friend Carl Laurin, is called “D.B. Cooper & Me: A Criminal, A Spy, My Best Friend.” and explains the story behind the mystery.
Whilst Reca died in 2014 at the age of 80, his identity is only just coming to light.
The evidence provided in the book has been analysed by forensic experts, despite the FBI no longer working on the case.
On November 24, the man hijacked a Boeing 727 and requested $ 200,000 (£132,000) in $ 20 notes. This amounts to a whopping £970,560 in today’s money.
He also requested food and drink for the cabin crew as well as four parachutes, before releasing everyone on board apart from three pilots and a flight attendant.
But after the plane took off again, he leapt from the plane with one of the parachutes when it flew over Portland, along with the money, and was never seen again.
His survival has been explained in the new book.
The author claims that Reca hit a tree and hurt his leg, before walking two miles to Tearaway Junction Cafe, according to the Mail Online.
He was then picked up by a friend of his called Don Brennan and went to work the next day after hiding the money.
Reca then worked for the government for the next 37 years doing covert work, before revealing his secret to Laurin in 2008.
Laurin spent years recording his story on tape, with some details that matched the FBI case confirming his suspicions.
These include using superglue on his fingers to hide his prints, as well as offering some of the money to a flight attendant before jumping.
It isn’t the first time the identity of DB Cooper was thought to be revealed. Theories surrounding his identity led to a man called Robert W Jackstraw who was a Vietnam War veteran.
He has continued to deny the claims, despite being investigated by the FBI in the 1970s.
He currently lives in San Diego at the age of 74.
A number of aviation mysteries remain unsolved even today.
One that has plagued many theorist’s minds is the mystery of Amelia Earheart’s disappearance over 80 years ago.