A man identifying himself as Dan Cooper hijacked a Northwest Orient jet, jumped from the airliner with $200,000 in ransom money and a parachute, and seemingly disappeared in 1971 in what Fox 13 calls "one of the most enduring FBI mysteries"—one a magazine hopes to solve.

True Ink has begun publishing hundreds of pages of FBI files in the hope that citizen sleuths will help solve the case, closed this year after the FBI "exhaustively reviewed all credible leads," per OregonLive.

True Ink founder Geoffrey Gray says he received the case files—including evidence assessments and interviews with jet passengers—while researching a 2011 book on the hijacker, later branded DB Cooper, but couldn't review them all, per the Washington Post.

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"We have access to all these original DB Cooper case files and we want help from the public, citizen sleuths to help solve this case," he says.

Authorities have had almost no leads in the decades since Cooper boarded the flight from Portland, Ore., to Seattle on Nov. 24, 1971. There are several theories about what happened to Cooper, however.

A retired FBI agent suspects he landed in a lake and died, though $5,800 in bills with matching serial numbers to the ransom money was found buried along the Columbia River in 1980.

Others believe Cooper was really Richard McCoy, who copied Cooper's crime in 1972 and was later killed in an FBI shootout. (Perhaps Cooper was a grocery manager from Michigan.)

This article originally appeared on Newser: DB Cooper Case Could Still Be Solved With Your Help