On 24 November 1971, a man using the alias "Dan Cooper" hijacked Northwest Orient Flight 305, extorted $200,000 in ransom, and parachuted from the aircraft over the Washington-Oregon wilderness, never to be identified. The FBI investigated more than 1,000 suspects over 45 years before formally suspending the investigation in 2016. In 2011, a citizen-science analysis of a partial ransom-bill find and particles on Cooper's abandoned tie produced new leads that also proved inconclusive.