Re-analyzing Evidence from the D.B. Cooper Hijacking Case
At a Glance
In this peer-reviewed study, Dr. Kent Rhodes (The McCrone Group) and co-author Dr. Thomas Kaye (Foundation for Scientific Advancement) demonstrate how modern microanalysis can uncover new forensic insights from decades-old evidence. Using automated field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDS), the team analyzed one stub that holds more than 180,000 microscopic particles recovered from Cooper’s clip-on tie. The findings reveal previously unrecognized industrial and mineral particles that provide new clues about the environment, industries, and activities potentially associated with the hijacker.
Issue
Dan Cooper, later known as D.B. Cooper, is the alias of an unidentified man who on on November 24, 1971, successfully completed the only unsolved commercial airline hijacking in U.S. history.
Cooper boarded Northwest Orient Airlines Flight 305, flying from Portland, Oregon, to Seattle, Washington. While in flight, he threatened the crew with a bomb, demanding a ransom of $200,000 and four parachutes. Upon landing in Seattle, where Cooper had negotiated the safe release of the flight’s 36 passengers for the money and parachutes, the plane took off again, flying toward Reno, Nevada. Once the plane was in flight over southwestern Washington state, Cooper leaped from the the aft airstair of the Boeing 727 and vanished forever. He did, however, leave his black clip-on necktie behind on seat 18-E.
The FBI recovered few pieces of physical evidence from seat 18-E: the necktie, a single strand of dark hair from the seat’s headrest, one limb hair from the armrest, and several cigarette butts from his seat’s ashtray. Of this material evidence, Cooper’s necktie is the only item that has not been destroyed.
The FBI investigation of the hijacking case remained open until July 8, 2016. Since then, the FBI released the evidence to the public, and citizen sleuths have continued to attempt to solve the case.
Stub #465 had previously been analyzed in 2016. Researchers suspected more information could be discovered due to improved analytical capabilities in current materials analysis instruments.
Solution
The 12mm Stub #465 was re-analyzed at McCrone Associates, utilizing a TESCAN MIRA4 thermal field emission scanning electron microscope employing the combined energy dispersive x-ray signal from four EDAX Element-V silicon drift detectors. Many more particles were identified than in 2016, and new particles of interest were identified that could offer clues to the identity of D.B. Cooper.
Beyond its historical significance, this research highlights the extraordinary value of advanced particle characterization and microanalysis in forensic investigations, illustrating how today’s analytical technologies can generate meaningful evidence from even the smallest trace materials and breathe new life into cold cases.
This project also demonstrates the power of McCrone Associates’ expertise in trace evidence characterization. Whether supporting forensic investigations, contamination studies, product failures, or complex materials identification, our scientists apply world-class microanalytical techniques to answer questions that conventional analytical methods cannot.
This article was originally published in the Journal of Forensic Sciences and is distributed under the Creative Commons Attribution 4.0 International (CC BY 4.0) License. © The Authors. Published by Wiley on behalf of the American Academy of Forensic Sciences. Available at: https://doi.org/10.1111/1556-4029.70372. Licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/).