In 1971, a man using the alias Dan Cooper bought a ticket for an airline flight from Portland, Oregon to Seattle, Washington. He hijacked the plane, then demanded a ransom of $200,000. After landing in Seattle, Cooper got his ransom money, released the passengers, then ordered the pilot to take off again. While over Washington, Cooper put on a parachute and jumped out of the plane with the ransom money.
He was never seen again.
Cooper, later called 'D.B. Cooper' by a confused media corps, became a national sensation. His amazing crime and disappearance captured the popular imagination. Law enforcement agencies hunted him, but with no success.
Now more 44 years later, the FBI is ready to close the case and end its decades-long investigation. In its press release, Public Affairs Specialist Ayn Dietrich-Williams writes that continuing the investigation is a poor use of limited resources:
Although the FBI appreciated the immense number of tips provided by members of the public, none to date have resulted in a definitive identification of the hijacker. The tips have conveyed plausible theories, descriptive information about individuals potentially matching the hijacker, and anecdotes—to include accounts of sudden, unexplained wealth. In order to solve a case, the FBI must prove culpability beyond a reasonable doubt, and, unfortunately, none of the well-meaning tips or applications of new investigative technology have yielded the necessary proof. Every time the FBI assesses additional tips for the NORJAK case, investigative resources and manpower are diverted from programs that more urgently need attention.
-via Laughing Squid
https://en.wikipedia.org/wiki/Cooper_vane