Well, Mr. Cooper, or whatever your name is, you've officially stumped the FBI. The agency announced Monday that it was no longer investigating the famous 1971 hijacking in which a passenger known as DB Cooper jumped out of a plane over Washington state with a parachute and $200,000 in cash, reports KIRO in Seattle. It is the only such unsolved hijacking in US history, and it appears that it will stay that way. "Following one of the longest and most exhaustive investigations in our history, on July 8, 2016, the FBI redirected resources allocated to the 'DB Cooper' case, in order to focus on other investigative priorities," says an FBI spokeswoman. It's not clear what prompted the FBI statement, but it comes just after a documentary aired on the History Channel in which former FBI detectives claimed to have cracked the case.