A new analysis of a tie left behind during the 1971 skyjacking turned up particles of cerium, strontium sulfide and pure titanium. The metals could have been used in the manufacture of certain aircraft or perhaps cathode ray tubes.

Share story

The FBI officially closed the file on D.B. Cooper last year, but that hasn’t stopped amateur detectives calling themselves  “Citizen Sleuths” from continuing to work the case.

The nation’s only unsolved hijacking has captured national attention and speculation and prompted hundreds of theories since November 1971, when a person calling himself Dan Cooper hijacked a Portland-to-Seattle flight and demanded $200,000 in cash, four parachutes and food for the crew.

About 45 minutes after Cooper let the passengers go and the crew took off from Seattle, Cooper donned a parachute, took the money and jumped out into the night somewhere north of Portland. Two remaining parachutes and a necktie were found where Cooper had been sitting.

Interest in the mystery was reignited nine years later when a young boy found three bundles of cash worth nearly $6,000 that matched the serial numbers of the money given to Cooper in the sand near the Columbia River.

This year, Tom Kaye of Citizen Sleuths told KING 5 News that a new analysis of the tie left on the plane shows particulate matter that indicates the wearer smoked cigarettes regularly and also may have worked in one of the very rare industries where cerium, strontium sulfide and pure titanium are used.

Kaye said those substances were used for Boeing’s high-tech Super Sonic Transport plane, developed in the 1960s and 1970s, and wondered if Cooper could have been a manager, consultant or engineer at Boeing. The amateur detectives also speculated that Cooper may have worked at a company that manufactured cathode ray tubes.

The testing of the tie was paid for by the Travel Channel television show “Expedition Unknown, which will replay the episode on D.B. Cooper and the Citizen Sleuths’ findings on Wednesday night at 8 p.m.

He and his group are asking for help from anyone who might be able to shed light on where that particular combination of metals could have been used.

“Someone may be able to look at those particles and say ‘Oh my gosh. I know what that means having those particles on the tie,’” Kaye told the TV station.