Kent Rhodes- Senior Vice President of McCrone Associates
https://www.mccrone.com/staff/kent-l-rhodes-ph-d/
Ph.D., Inorganic Chemistry, Northwestern University, 1990
M.S., Inorganic Chemistry, Northwestern University, 1986
B.S.S., Chemistry and Mathematics, Cornell College, 1985
Invited by UI's Dept of Chemistry- Chemistry Grad Student Association
"Automated Particle Analysis: Solving the D. B. Cooper Mystery with Chemistry?"
Abstract: Automated particle analysis (APA) uses scanning electron microscopy (SEM) with energy-dispersive X-ray spectrometry (EDS) to measure the size, shape, and elemental composition of thousands to millions of individual particles. APA combines high-resolution SEM imaging and EDS microanalysis with automation and large-scale data processing to enable studies that are impossible to perform manually.
APA is well known in criminal forensics, especially for gunshot residue analysis. APA excels at both targeted searches for specific materials and characterization of complex particle populations. It is particularly useful for the classic “needle-in-a-haystack” problem, where a few characteristic particles may reveal critical evidence. APA’s large datasets are excellent targets for exploratory data analysis.
This presentation explores how APA is being applied to the enduring mystery of the 1971 D. B. Cooper hijacking. APA was performed on particles lifted from Cooper’s tie, which was left on the hijacked plane. Using a customized SEM-EDS instrument, approximately 180,000 particles removed from Cooper’s tie were imaged and chemically analyzed. The analysis revealed many unusual particles, including industrial metals, possible aerospace materials, and rare-earth compounds. These may be clues to the background of the Cooper hijacker.
Beyond these distinctive materials, hundreds of thousands of “environmental background” particles in the Cooper dataset may be a heretofore underutilized source of forensic value. For example, APA shows clays, smectites, and feldspars to be more abundant than zeolites, a distribution being investigated for geochemical sourcing. These particle signatures may offer insight into the geographic areas Cooper frequented.
Cooper’s tie is the only remaining material evidence in the case. This study illustrates how modern automated microanalysis can transform even decades-old evidence into new leads through the power of data-rich, high-throughput chemistry.