(Newser) – 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.

They name 72-year-old Robert Rackstraw, who now lives on a boat in a yacht harbor in San Diego Bay, reports the Monterey Herald. Rackstraw—who allegedly tried to fake his own death in 1978 by, yes, bailing out of a plane—denies the allegations through his attorney. "He's not DB Cooper," says the lawyer, though he acknowledges that his client may have floated the claim himself over the years. Of course, this isn't the first DB Cooper theory and probably won't be the last. Some think Cooper never survived the jump, pointing to the discovery of some of the cash by the Columbia River in 1980, notes the New York Daily News. But "the FBI exhaustively reviewed all credible leads," says the FBI spokeswoman. Still, she adds, if hard evidence emerges, investigators would be back on the job. (Another theory suggests Cooper was a grocery store manager from Michigan.)

