Robert Rackstraw loved adventure. He also embraced danger and confrontation. For a time, the FBI suspected him of being the legendary skyjacker known as D.B. Cooper.

Rackstraw died Tuesday in San Diego of natural causes. He was 75. He is survived by his wife Dorothy and “several children and grandchildren,” the San Diego Union-Tribune reports.

Born in Ohio in 1943, the high-school dropout became a decorated U.S. Army paratrooper during the Vietnam War in the late 1960s before being run out of the military for lying and other misconduct. He pursued various jobs and diversions in the years that followed, leading to trouble with the law.

He was acquitted in 1978 of murdering his stepfather. Soon after the acquittal, facing other charges, he faked his death and disappeared. He ultimately would be found and convicted of grand theft and passing bad checks. He spent almost two years in prison.

The prosecutor in the theft-and-forgery case, San Joaquin, Calif., deputy district attorney Clark Sueyres, called him “a helluva con man. You’d buy a used car from him every time.”

Along with his exploits in California, Rackstraw also spent time in Oregon — beyond the possibility that he purchased a plane ticket at Portland International Airport on Nov. 24, 1971, under the name Dan Cooper.

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Entrepreneur Eric Ulis has been researching the famous skyjacking for years. And like many Cooper sleuths before him, he believes he’s solved the mystery.

Robert “Pudgy” Hunt, a celebrated Oregon high-school basketball player and long-time Portland tavern owner, worked in the flooring business with Rackstraw in the 1970s.

Hunt agreed with the California prosecutor that Rackstraw had charisma to burn. And that he couldn’t be trusted.

Hunt’s brother, he said, witnessed Rackstraw savagely beat a union worker who gave him some back talk on a job site. Hunt later heard from another first-hand source that in California Rackstraw stole a truck and smashed it through the front doors of a gun shop before driving off with a cache of weapons.

It might have been inevitable, then, that Rackstraw would be linked to the famous — and famously unsolved — D.B. Cooper case. In the late 1970s, the FBI considered Rackstraw a suspect for a while before moving on, in part because witnesses said the skyjacker was in his 40s. (Rackstraw was 28 in 1971). A reporter at the time asked Rackstraw if he were Cooper, and the Vietnam War vet gave a cryptic answer, saying that if he were investigating the case, “I wouldn’t discount myself.” Years later Rackstraw insisted he was winding the reporter up and that he wasn’t D.B. Cooper.

The FBI closed the D.B. Cooper case without resolution in 2016. Colbert, three years later, now has done the same.