SEATTLE (AP) — The FBI says it has a "credible" lead in the D.B. Cooper case involving the 1971 hijacking of a passenger jet over Washington state and the suspect's legendary parachute escape.

The fate and identity of the hijacker dubbed "D.B. Cooper" has remained a mystery in the 40 years since a man jumped from a Northwest Orient Airlines 727 flight with $200,000 in ransom.

The recent tip provided to the FBI came from a law enforcement member who directed investigators to a person who might have helpful information on the suspect, FBI spokeswoman Ayn Sandalo Dietrich told The Seattle Times on Sunday. She called the new information the "most promising lead we have right now," but cautioned that investigators were not on the verge of breaking the case.

"With any lead our first step is to assess how credible it is," Sandalo Dietrich told the Seattle Post Intelligencer on Saturday. "Having this come through another law enforcement (agency), having looked it over when we got it - it seems pretty interesting."

Dietrich says an item belonging to the man was sent to a lab in Quantico, Va., for forensic testing. She did not provide specifics about the item or the man's identity.

Federal investigators have checked more than 1,000 leads since the suspect bailed out on Nov. 24, 1971, over the Pacific Northwest. The man who jumped gave his name as Dan Cooper and claimed shortly after takeoff in Portland, Ore., that he had a bomb, leading the flight crew to land the plane in Seattle, where passengers were exchanged for parachutes and ransom money.

The flight then took off for Mexico with the suspect and flight crew on board before the man parachuted from the plane.

The FBI's recent tip in the case was first reported by The Telegraph newspaper in London.