In the years following the 2016 suspension, researchers continued to push for the release of additional FBI case documents through the Freedom of Information Act. The FBI’s Vault—its public records portal—has made portions of the Cooper file available over time. These releases have given independent researchers access to information about suspects, investigative theories, and laboratory analyses that was previously restricted.
The tie analysis that revealed more than 100,000 microscopic particles, including bismuth and unalloyed titanium, emerged from documents released or discussed after 2016. Researchers who have examined this information have offered various interpretations, including the hypothesis that the particle profile might be consistent with work in an aerospace manufacturing environment. The FBI has not adopted a specific interpretation or confirmed that the particle analysis points toward a particular suspect or background.
In 2019, Robert Rackstraw—who had been publicly named as a Cooper suspect in a 2016 book—died without being charged or identified by the FBI as the hijacker.
The COVID-19 pandemic and its disruptions in 2020 and 2021 did not generate any new evidence in the Cooper case, but the period saw continued online research activity and renewed public interest as streaming documentary series and true crime podcasts took up the case.
No verified identification of Dan Cooper has been made as of 2026.
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## Why Cooper Probably Didn’t Survive—and Why We Can’t Be Certain
The question of whether Cooper survived is one that investigators, researchers, and ordinary people have debated for more than fifty years. It is worth setting out the arguments on both sides honestly.