VIDEO: The Disappearance of D.B. Cooper. New Leads on the Case

There are many interesting cases that no one was able to crack. While most of them are criminal cases in which a lot of people died, there are some that just involve a lot of money.

One of the most interesting cases that still baffles people to this day is the case of the famous D. B. Cooper who has become famous across the world for the way he hijacked a plane and ran away and was never seen again.

According to washingtonpost.com, it was “one of the longest and most exhaustive investigations” in FBI history — and to this day remains the only unsolved skyjacking in the United States.

In 1971, a well-dressed passenger hijacked a Northwest Orient flight, demanded $200,000 and later escaped by parachuting out of the back of the plane with the ransom money.

But who exactly was “D.B. Cooper,” the mysterious man who managed to pull off the heist and disappear without a trace?

More than four decades later, three amateur scientists think they may have found evidence that would narrow down Cooper’s identity to that of an aerospace engineer or a manager.

The scientists, working for a group called Citizen Sleuths, said they have been analyzing particles found on a clip-on necktie that Cooper left on his seat — 18E — before jumping out of the plane.

To the naked eye, the piece of fabric was a nondescript black tie from J.C. Penney. But to the modern-day scientists, the tie was an “incredibly fortunate” piece of evidence in the investigation.

“A tie is one of the only articles of clothing that isn’t washed on a regular basis,” reads a section on the Citizen Sleuths website devoted solely to the tie.

“It picks up dirt and grime just like any other piece of clothing, but that accumulation never truly gets ‘reset’ in the washing machine. Each of those particles comes from something and somewhere and can tell a story if the proper instruments like electron microscopes are used.”

Using a powerful electron microscope, the scientists say they have identified more than 100,000 particles of “rare earth elements” on the tie, including Cerium, Strontium sulfide and pure titanium, according to the Associated Press. Of those, titanium was the most notable.

“Titanium was a rare metal in 1971 and this makes it extremely unlikely it is a post-event contamination,” Citizen Sleuths notes on its site, which lays out in painstaking detail all of the findings from the case.

“Its presence constrains Cooper to a limited number of managers or engineers in the titanium field that would wear ties to work.”

At the time, they noted, the element was used extensively by the military in aircraft and helicopters.

Scientists think he may have worked at Boeing, which at the time happened to be developing a Super Sonic Transport plane that used those elements, Tom Kaye, a lead researcher with Citizen Sleuths, told King 5 News.

The mystery began on Nov. 24, 1971, when a nondescript man going by the name of Dan Cooper purchased a one-way ticket from Portland, Ore., to Seattle directly from the Northwest Orient Airlines counter on the day of the flight.

He used cash to pay for his ticket, then boarded the plane. Authorities later described him as someone in his mid-40s, dressed as an “executive” in a suit, a white shirt and what probably is the now-infamous black tie.