The FBI says it's no longer actively investigating the unsolved mystery of 1970s plane hijacker D.B. Cooper.

The bureau announced Tuesday that it's "exhaustively reviewed all credible leads" during its 45-year investigation and has redirected those resources to other priorities.

The FBI has investigated since a man calling himself Dan Cooper hijacked a Boeing 727 over the Northwest on Nov. 24, 1971. He later jumped out the back of the plane wearing a business suit and a parachute after receiving $200,000 in ransom money.

No sign of Cooper has emerged, though bundles of his cash, matched by serial numbers, were found in 1980.

The FBI says it has conducted searches, collected all available evidence and interviewed all identified witnesses. It says it's chased an immense number of tips but none have resulted in identifying the hijacker.