Nuclear bombshell could FINALLY crack infamous DB Cooper case... and tragic clue that suggests 'wink-and-nod' about his motive

Microscopic evidence gleaned from a clip-on tie left behind by mysterious plane hijacker DB Cooper has the case's lead independent investigators turned in a new direction that could finally unmask the suspect, Daily Mail can reveal. 

On November 24, 1971, a well-dressed, middle-aged man identifying himself as Dan Cooper hijacked Northwest Airlines Flight 305 during a trip between Portland, Oregon, and Seattle, Washington.

Cooper told a flight attendant that he had a bomb in his briefcase and demanded $200,000 in stacks of $20 bills and four parachutes in exchange for the lives of the 42 people on board.

The ransom was hand-delivered to him upon arrival in Seattle. After the exchange Cooper ordered the pilots of the Boeing 727 to refuel and fly towards Mexico. 

A short while later, 10,000ft over southwest Washington, Cooper lowered the aircraft’s rear aft staircase and leapt from the plane with two of the parachutes and the ransom strapped to his waist - and he was never seen again.

Hundreds of suspects have been investigated over the last 50 years, but no arrests have ever been made in one of the most notorious unsolved mysteries in U.S. history.

One of the only traces left behind by Cooper was a JCPenney clip-on tie that he removed before taking his storied leap of faith.

Now a speck of a chemical on the discarded tie has opened the door to an explosive theory that could finally reveal the true identity of the elusive suspect.

The FBI closed its investigation into Cooper in July 2016, but the tie remains in the bureau’s possession. Only a handful of people have ever been allowed access to it.

One of those people is Tom Kaye, a scientist who has twice tested the crucial artifact for the FBI in 2009 and 2011, looking for traces of certain metals, chemicals, and pollen - tiny clues that could help to unravel the mystery of Cooper’s true identity.

The FBI did recover a partial DNA profile from Cooper’s tie but repeated requests made by Kaye and independent investigator Eric Ulis to access that data have been denied.

In search of answers, Kaye and Ulis have recently been retesting Kaye’s decade-old tie samples using state-of-the-art technology and uncovered a series of rare particles consistent with specialty metals from the aerospace sector.

It has long been believed Cooper had ties in the aerospace industry because of his near-constant use of aviation jargon during the heist and his seemingly intimate knowledge of the inner workings of the Boeing 727.

Last year, Kaye and Ulis discovered traces of a rare particle, consisting of pure titanium smeared with stainless steel, which is generated in a metalworking process known as ‘cold rolling.’

The existence of the particle pointed the sleuths in the direction of a now-defunct specialty metals facility in Pittsburg, Pennsylvania, called Rem-Cru Titanium, where they believed Cooper may have worked as a metallurgist.

Rem-Cru was a major supplier of titanium and stainless steel parts for Boeing during the 1960s and 70s and had two patents for the rare particle Kaye and Ulis identified.

Following an exhaustive investigation, scouring years of employment records at Rem-Cru and interviewing former employees, Ulis named engineer Vince Peterson as his leading Cooper suspect.

Peterson, who died in 2002, would have been 52 at the time of the skyjacking and matched eyewitness descriptions of Cooper shared by those onboard Flight 305.

Peterson’s daughter, Julie Dunbar, staunchly denied Ulis’ allegations, insisting her father would never have abandoned his family during the Thanksgiving holiday to hijack a plane for ransom.

And now, it appears Peterson has been vindicated as a suspect in Ulis and Kaye’s probe following the discovery of yet another exceedingly rare particle on Cooper’s tie.

That particle is a compound of thorium and uranium, which Ulis said was the ‘single most important particle ever discovered on Cooper’s tie'.

In an exclusive interview with the Daily Mail, he explained: ‘The reason why is because it appears to relate to an alloy that was being worked on in the latter half of the 1960s as a prospective nuclear fuel for a very specific type of nuclear reactor called a molten salt reactor.'

While Ulis and Kaye still believe the evidence on Cooper’s tie shows he was likely some kind of metallurgist or engineer, they no longer believe he worked at Rem-Cru and, therefore, cannot have been Vince Peterson.

Instead, Ulis’ extensive research has led him now to the Oak Ridge National Laboratory on the outskirts of Knoxville, Tennessee, as Cooper’s potential place of employment.

In the late 1960s, Oak Ridge was conducting the ‘lionshare’ of work in the U.S. concerning experiments with molten salt reactors, Ulis said.

The plant - then owned by Union Carbide, a major contributor to the first atomic bomb - was also working on plans to develop a nuclear-powered aircraft for the US military, once again identifying a potential link between Cooper and the aerospace industry.

Boeing was involved in that project, Ulis said, adding that Oak Ridge also worked regularly with titanium and alloys - accounting for his earlier particle discovery.

But Cooper’s prospective ties to Oak Ridge don’t end there.

During the hijacking of Flight 305, Cooper smoked several cigarettes, believed to be Raleigh filter-tipped cigarettes, that he lit using a book of matches from a chain of airport restaurants called SkyChefs.

In 1971, SkyChefs had 16 locations in airports across the U.S., one of which was located in the McGhee Tyson Airport near Knoxville.

According to Ulis, who obtained an identical matchbook to the one Cooper was carrying, the locations of the restaurants were listed on the inside of the matchbook sleeve.

‘McGhee Tyson is the airport you’d be going in and out of if you were traveling to the area, so that’s an intriguing thing to consider that perhaps DB Cooper stayed in that area, or frequently flew in and out of that area with his possible work at Oak Ridge, and that’s why he had the matchbook,’ said Ulis.

In another fascinating discovery, Ulis believes he may have unearthed the origins of Cooper’s alias - or at the very least a compelling coincidence.

Dan Cooper was the name listed on the crook’s airplane ticket. However, he later became known as D.B. Cooper after a reporter mistakenly mistyped his name in an early news report and it caught on.

Ulis found out that there was a longtime employee of Oak Ridge by the name of Ralph Cooper who worked at the lab from 1962 to 1997.

Ralph had a brother named Dan Cooper, who was accidentally shot dead by police in August 1960.

According to news reports from the time, Dan Cooper was killed while helping law enforcement search for a fugitive cop killer near his home in Heiskell, Tennessee. His father, Kaley Cooper, was also shot but survived.

The Cooper family later sued the local sheriff, seeking $400,000 in damages: $200,000 for the death of Dan Cooper and $200,000 for the injuries sustained by Kaley Cooper.

Ulis said it’s his understanding that the family lost the Kaley Cooper suit. He pointed out that the $200,000 the Cooper family missed out on is the same sum requested by D.B. Cooper a decade later in 1971.

There is no concrete evidence linking the shooting of Dan Cooper to the D.B. Cooper heist, but Ulis said it’s a lead ‘worth looking into.’

He does not believe Ralph Cooper could’ve been D.B. Cooper, noting Ralph was only 35 at the time of the heist, which is more than a decade younger than the skyjacker eyewitnesses placed as being in his mid-to-late 40s.

However, Ulis theorized it’s possible that D.B. Cooper was a colleague of Ralph’s and used his brother’s name as an alias in a ‘wink-and-nod’ reference.

‘It’s possible that D.B. Cooper knew of this story because it was well reported in the media at the time,’ said Ulis.

‘Maybe it was a subtle reference, or maybe it’s just a name he subconsciously latched onto.

‘Who knows? But it’s something interesting to consider as this investigation moves forward.’

Much like D.B Cooper’s identity, the crook’s motive for committing the hijacking of Flight 305 is a mystery.

While certainly motivated by financial gain, it’s an infamous line the mild-mannered Cooper muttered to a flight attendant during the in-air heist that lives on in infamy and adds further intrigue to the already enthralling puzzle.

When asked by Tina Mucklow why he chose to hijack a Northwest Airlines flight, Cooper laughed and told her: ‘I don’t have a grudge against your airline, I just have a grudge.’

In the tentative stages of his latest angle of investigation, Ulis suggested the grudge mentioned by Cooper may have had to do with mass layoffs at Oak Ridge/Union Carbide in the late ‘60s and ‘70s that came as a result of federal government sanctions.

Oak Ridge’s Molten Salt Reactor experiment was shut down by the company in 1969, a few years after its unsuccessful attempt to deliver a nuclear-powered military aircraft, Ulis said.

He further explained: ‘The reason for shutting the reactor experiment down was because the federal government made a decision to pursue another type of nuclear energy and they cut their funding by two-thirds, which led to roughly 1,200 of its 5,000 employees being laid off in 1969.

‘So when you look at D.B. Cooper, who was a guy of around 50 who was well educated and some sort of metallurgist engineer, and there’s no indication he was a career criminal, there’s got to have been an event in his life that precipitated this guy deciding to hijack a plane in 1971.

‘I’ve always thought what makes the most sense is some kind of economic distress, so getting laid off or fired.’

Ulis said it is his working theory that perhaps Cooper was laid off from Oak Ridge in 1969 or possibly moved to another Union Carbide-owned facility before being laid off again in 1971.

‘Union Carbid had six metal divisions across the United States, one of which was in Oak Rodge, one of which was coincidentally in Portland, Oregon, and then another was in a place called Marietta, Ohio,’ shared Ulis.

‘The interesting thing about Marietta, Ohio, is that in 1971, the federal government was really coming down hard on Union Carbide about cutting their pollution down, specifically at the plant in Ohio, and eventually the government mandated them laying off hundreds of employees - basically half of the people employed there.

‘So one can envision a situation where perhaps, perhaps DB Cooper, within a matter of two short years, actually experienced two layoffs or two sort of life-altering situations financially, and maybe that has something to do with it.

‘That’s certainly something we’re looking into.’

Ulis said the latest discovery yielded from Cooper’s tie has breathed fresh life into his more-than-decade-long quest to unmask the skyjacker.

So buoyed by the discovery, Ulis believes he may be able to crack the case within the year.

'It's all very intriguing, science-based, and fact-driven, and I’m very excited about the process. I think there’s a real possibility we figure out who this guy was before the end of the year,’ beamed an optimistic Ulis.

Helping to dig deeper into the history of Oak Ridge is Ulis' uncle, a retired nuclear engineer who had colleagues who worked at the lab. 

‘I really feel like we’re getting closer to solving this mystery once and for all.’