Editing D. B. Cooper (section)

===Sheridan Peterson===
[[File:Cooper-Peterson.jpeg|thumb|The 1971 sketch of Cooper's description, and photo of Peterson from around the same time]]
Sheridan Peterson (1926–2021) served with the Marine Corps during World War II and was employed later as a technical editor at Boeing, based in Seattle. Investigators became interested in Peterson as a suspect soon after the skyjacking because of his experience as a [[smokejumper]] and love of taking physical risks, as well as his similar appearance and age (44) to the Cooper description. His involvement in the [[civil rights movement]] and assisting refugees in Vietnam during the Vietnam War could have potentially radicalized him to pursue hijacking.<ref name="Douglas">{{cite web|author=Perry|first=Douglas|date=January 28, 2021|title='Charming' D.B. Cooper suspect Sheridan Peterson dies at 94, spent years dedicated to political causes|url=https://www.oregonlive.com/history/2021/01/charming-db-cooper-suspect-sheridan-peterson-dies-at-94-spent-years-dedicated-to-political-causes.html|access-date=January 30, 2021|archive-date=January 30, 2021|archive-url=https://web.archive.org/web/20210130173740/https://www.oregonlive.com/history/2021/01/charming-db-cooper-suspect-sheridan-peterson-dies-at-94-spent-years-dedicated-to-political-causes.html|url-status=live}}</ref>

Peterson often teased the media about whether he was really Cooper. Entrepreneur Eric Ulis, who spent years investigating the crime, said he was "98% convinced" that Peterson was Cooper; when pressed by FBI agents, Peterson insisted he was in Nepal at the time of the hijacking. He died in 2021.<ref name="Douglas" />

In an episode of History Channel's ''History's Greatest Mysteries'', analysis of DNA found on the tie worn by Cooper indicated that Peterson was not a match for Cooper when compared to a DNA sample from one of Peterson's living daughters. Eric Ulis has since withdrawn his allegation that Peterson could have been Cooper.