NEW FBI files have shed light on one of the longest-running unsolved hijackings in US history.

A 398-page document compiles decades of tips on DB Cooper – the mysterious man who hijacked a plane in 1971 before parachuting away with $200,000 in ransom money.

Dan “DB” Cooper is the alias of the man who hijacked Northwest Flight 305 over Portland, Oregon, in November 1971, en route to Seattle.

Described as a dark-haired man in his mid-40s, Cooper passed a flight attendant a note claiming he had a bomb in his briefcase – which he showed to contain wires and red sticks.

After the Boeing landed in Seattle, Cooper released 36 passengers in exchange for $200,000 in cash and four parachutes.

The plane then took off with several crew members, heading towards Mexico City under Cooper’s orders.

Somewhere between Seattle and Reno, Nevada, at around 10,000 feet, Cooper parachuted from the back of the jet with the ransom money – never to be seen again.

The document, released by the FBI on Tuesday, reveals that despite interviewing hundreds of suspects, the agency remains at a dead end.

One suspect was even a man in a wheelchair, with the report concluding: “A man confined to a wheel chair [sic] did not hijack the plane in this case.”

While multiple suspects are named in the files, further investigation – including showing photos to witnesses – often led agents to mark their files with a handwritten “eliminated”.

The files include the well-known claim by Donald Sylvester Murphy that he was DB Cooper.

Murphy made this claim to a former Newsweek editor, but it was later revealed to be part of an extortion scheme.

The elaborate plot saw Murphy posing for photographs “wearing a wig and glasses and otherwise appearing much like the widely circulated ‘artist’s conception’ of ‘D.B. Cooper,’” according to a court document included in the files.

Murphy and a conspirator were sentenced to prison for the fraud, according to a 1973 report by The New York Times.

Notably, Richard McCoy Jr., whose children claimed he was DB Cooper last year, does not appear in the files.

In fact, most suspects remain unknown to the public.

They range from an Alabama man who died of cancer just months after the hijacking, to airline pilots, parachutists and Boeing employees.

The Sun previously reported on independent investigator Eric Ulis’ probe into the DB Cooper case.

In August last year, Eric identified Vince Petersen, a deceased metallurgist from Pennsylvania, as his leading suspect – a theory he has pursued since 2022.

Eric and forensic expert Tom Kaye discovered dozens of rare titanium particles on a clip-on tie left behind by the hijacker.

Tracing the particles led them to the now-defunct Crucible Steel plant in Midland, Pennsylvania, where Petersen worked for several years.

Meanwhile, a passenger aboard the plane shared their memory of the elusive criminal with The Sun.

Michael Cooper, a then 31-year-old teacher traveling home for Thanksgiving, remembered the hijacker as a suave and level-headed man who exuded authority.

“He was probably in his 40s, and he was wearing a jacket and a tie and he was just real quiet,” Michael said in January last year.