The identity of DB Cooper has mystified global audiences for more than half a century.
People have been desperate to put a name and background to the man who decided to hijack the Northwest Orient Airlines Flight 305 on 24 November, 1971.
DB Cooper, not his real name of course, demanded $200,000 (£157,000) - the equivalent of around $1.5 million (£1.18 million) nowadays.
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If the money wasn't handed over, he said he'd blow up the plane with a bomb he had in a briefcase.
The hijacker disappeared into the night, after parachuting into the darkness with his money.
Since then, he's never been identified by the FBI. The case was officially closed in 2016 - but fresh hope remains that he could be traced by the end of 2024.
In the 53 years since the how infamous hijacking, a number of names and faces have been put forward to try and solve the case.
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Among them was a woman, named Barbara Dayton.
Born in 1926, Dayton was a recreational pilot and University of Washington librarian.
With big dreams of becoming a pilot for her day job, she embarked on obtaining her licence.
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But the big day that she sought never came, with her twice failing the written portion of the test.
Dayton was also trans, having undergone gender reassignment surgery, after being born as a man. She had felt 'trapped in the wrong body' during her childhood and adulthood, according to close friends Ron and Pat Forman.
Just over a week before the hijacking, Dayton had visited with hospital staff as part of a follow-up visit to her surgery to become a woman.
Reports claim she had low mood and was depressed, and also low on cash with little work coming in.
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The Formans, who wrote the book The Legend of D.B. Cooper, reveal that during their friendship she opened up to them on her transition having only ever known them post-surgery.
But she also told them she was the infamous DB Cooper - a claim she would later renege on.
They explain: "Barb had confessed to us that she was D.B. Cooper, but initially we weren’t going to include that in our book.
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"However, when we met the family, we found that they also were suspicious that Barb was Cooper.
"As we got to know them, we became convinced that it was important to try to investigate the possibility. It was evident that the family did not condone what the skyjacker had done, but it was also evident that the investigation would provide some sort of closure for the family.
"It would be the ultimate proof of how strong the turmoil inside of Barb was and explain away some of the hurt she had caused by deserting her family to become a female.
"The skyjacking was not done for the money. The reasons she gave for the skyjacking were losing a house because of back taxes, not being able to become a commercial pilot due to FAA rules, and not being able to fit into society even after going through the pain and suffering of the gender reassignment."
Her close friends were confused over the situation, with Dayton not matching the description given by flight attendants who were with DB Cooper on the plane.
Dayton's eye colour was different, she was shorter than the description given to the FBI.
Dayton died in 2002. After then, the Formans took her confession to the FBI who reportedly threw it out. She simply wasn't tall enough, they said.
The case on who DB Cooper might be closed, but who he was will remain very much open until we have a name.