The FBI has given up the hunt for the man known as D.B. Cooper, the suspect in a 45-year-old plane hijacking that will now remain one of the bureau's most notorious unsolved crimes.
The last agent assigned to the case has been asked to work on "other investigative priorities," leaving the identity and whereabouts of a man wanted in the 1971 hijacking of a Northwest Orient Airlines flight unknown.
After flashing what appeared to be a bomb and demanding the flight crew "fly to Mexico," the man who called himself Dan Cooper jumped from the plane into driving wind and rain somewhere between southern Washington state and Oregon on Nov. 24, 1971, officials said.
He was outfitted with just a parachute and was clutching $200,000 in ransom money when he leapt from the jet, which was heading to Nevada from Seattle.
Ever since, investigators had poured over evidence and tips that came in with theories, descriptive information and anecdotes that law enforcement officials hoped would explain Cooper's fate.
“Unfortunately, none of the well-meaning tips or applications of new investigative technology have yielded the necessary proof,” FBI spokeswoman Ayn Dietrich-Williams said in a statement Tuesday, calling the manhunt "one of the longest and most exhaustive investigations in" FBI’s history.
“Every time the FBI assesses additional tips for the NORJAK case, investigative resources and manpower are diverted from programs that more urgently need attention,” she said.
The bureau consistently appealed to the public’s help in solving the decades-old case, releasing new information on the investigation as recently as 2007.
Sharing a picture of the J.C. Penney tie Cooper wore during the hijacking and photos of some of the stolen $20 bills found by a boy along the Columbia River in 1980, the FBI asked readers to “look it all over carefully to see if it triggers a memory or if you can provide any useful information.”
Authorities said they did not believe Cooper was an experienced skydiver or that he had an accomplice.
“No experienced parachutist would have jumped into the pitch-black night, in the rain, with a 200-mile-an-hour wind in his face, wearing loafers and a trench coat,” Special Angel Larry Carr, who was assigned the case, said in 2007.
Investigators looked into all possible leads, including the deathbed confession of Duane Weber, who said he was the infamous outlaw but was ruled out using DNA testing as the bureau “lifted a DNA sample from Cooper’s tie in 2001.”
A deceased World War II veteran and former paratrooper named Kenneth Christensen once suspected by his brother to be Cooper was also ruled out, as was Richard McCoy, who was confirmed to be with his family in Utah the day after the hijacking.
“An unlikely scenario unless he had help,” the FBI wrote at the time.
Other officials doubt Cooper even survived the jump.
“Diving into the wilderness without a plan, without the right equipment, in such terrible conditions, he probably never even got his chute open,” Carr said in 2007.
The most recent lead came in 2011, when a woman claimed her uncle may have been the skyjacking outlaw. However, DNA collected from Cooper's was not a match.
Though the FBI is no longer actively investigating the case, the agency will keep its evidence filed away and will continue to field tips, officials said.