On Nov. 24, 1971, a man who called himself Dan Cooper hijacked a Northwest Orient Airlines passenger flight, stole $200,000 in ransom money, and then parachuted out of the plane to never be seen again.
The case spurred international attention and public speculation about who D.B. Cooper could be, and prompted a decades-long manhunt. But to this day, the FBI hasn't been able to identify the suspect.
Now, nearly 45 years later, the FBI said Tuesday it is ending one of its "longest and most exhaustive investigations" in history.
The FBI says it will no longer be actively investigating the D.B. Cooper case, and will redirect resources to focus on other priorities.
The FBI says it reviewed all credible leads, collected all available evidence, and interviewed all identified witnesses. But "unfortunately" none of the tips or evidence have "yielded the necessary proof" to solve the case, the agency notes.
But if "specific physical evidence" emerges related specifically to the parachutes or the money taken by the hijacker, people are asked to contact their local FBI field office.
Cooper had purchased a one-way ticket from Portland to Seattle on Northwest Orient Flight 305.
While aboard the plane, he told a flight attendant he had a bomb in his briefcase.
Once the plane landed in Seattle, the suspect traded the passengers for $200,000 in $20 bills and four parachutes.
He kept several crew members on the flight and demanded to be taken to Mexico. But not long after takeoff, he took the money and parachuted out of the plane over the northwestern United States.
He was never seen again.
But tips about possible theories, potential descriptions of the hijacker, and stories about someone's sudden and unexplained wealth came pouring in.
Some believe he didn't survive the jump. The FBI says the theory was given a "boost" back in 1980 when a boy found a rotting package of $5,800 worth of $20 bills – all matching the ransom money's serial numbers.
The FBI says five years after the hijacking, the agency had considered more than 800 suspects, and eliminated all but two dozen from consideration.
And the tips have continued to come in. Just this week, a new book and a History Channel TV special claimed a 72-year-old California man was the hijacker – but it's a report the man has denied, the Monterey Herald says.
The evidence obtained during the FBI's investigation will be "preserved for historical purposes" at the FBI headquarters in Washington, D.C., the agency says.