Any true crime enthusiast knows the story of D.B. Cooper by heart.
On Nov. 24, 1971, a man who was never identified other than by his alias Dan Cooper (later known as D. B. Cooper), highjacked a Boeing 727 on its way Seattle — saying he had a bomb, and demanded $200,000 and parachutes after the plane landed at its destination. Cooper demanded the plane then travel to Reno from Seattle and then to Mexico City, which it did until Cooper jumped out of the plane with the money somewhere over Washington.
He was never heard from again, marking one of the greatest mysteries ever investigated by the FBI.
For four decades, the case was investigated by the FBI with hundreds of suspects investigated by the organization. However, a conclusion was never drawn on the true identity of Cooper and in 2016, the active case was closed by the FBI.
In the age of true crime, a number of sleuths have taken it upon themselves to continue the search for Cooper, including Eric Ulis. Ulis is the founder of CooperCon, and has been featured on the History Channel, Netflix and the Discovery Channel for his research.
One item that has been extensively investigated and debated is Cooper's clip-on tie from J.C. Penney, which was left behind on the plane before he jumped.
Fragments on the tie contained pure titanium, aluminum, stainless steel and other metals, which Ulis now believes links Cooper to Pratt & Whitney in East Hartford.
Ulis, like many other sleuths, believes that Cooper had extensive knowledge of the Boeing 727 aircraft and specifically, the JT8D engine. The FBI even investigated whether Cooper could have worked for the Boeing company.
However, Ulis believes that the mix of elements, including Earth elements found on the tie, point to Cooper potentially working Pratt & Whitney in the late 60's.
"In the case of the titanium being commercially pure, that limits things even further," Ulis wrote to CT Insider. "The JT8D used several hundred pounds of commercially pure titanium — again, quite unusual in aerospace given that the vast majority used in aerospace was alloyed."
Ulis wrote that Pratt & Whitney and Boeing worked extensively during the development of the Boeing 727, specifically in regards to the JT8D engine. The Pratt & Whitney JT8D, which was introduced in the early 1960's, became the popular choice for commercial planes, with it being used on nearly half of all commercial planes in 1985, according to the New York Times.
"The three engines happened to be situated in the very back cone area of the jet that D.B. Cooper used to exit mid-flight. The specifics of his knowledge would not have been easy to acquire back in the late 60s and early 70s," Ulis continued.
Additionally, salt, bentonite clay, feldspar and a type of “sand” mixture were found on his tie, which are found in sand and salt that is applied to roads during winter, which "has the net effect of making it a lot less likely that Cooper would have come from California, for example," Ulis added.
Another main argument for Cooper working at Pratt & Whitney was the volatile nature of the aerospace sector in 1971, following Congress cutting funding for projects like the Boeing SST 2707 project. The project was something that Pratt & Whitney competed for.
"The loss was seen as a major blow to Pratt & Whitney's future," reads Pratt & Whitney's website. "By 1971, however, the issues of sonic boom, emissions in the ozone layer and lousy economics killed the U.S. program."
"There are a number of things that suggest D.B. Cooper was not a career criminal, that he was well educated, that he was familiar with the aerospace sector and that he did not live in the Pacific Northwest, but was familiar with the region," Ulis noted about Cooper.
Still, the identity of Cooper continues to remain a mystery — one that may or may never be solved.