The mystery of D.B. Cooper's hijacking and disappearance lives on 50 years later in the Pacific Northwest

It has become a familiar story in the Pacific Northwest, if not beyond. As with so many infamous unsolved mysteries, just the name — D.B. Cooper — can raise the hair on a neck and inspire wonder.

Wednesday marks 50 years since a mystery man known widely as D.B. Cooper ("Dan Cooper" was the name he used for his one-way ticket) leapt from a Boeing 727's rear stair door with $200,000 somewhere over Southwest Washington. It remains the only unsolved case of air piracy in U.S. history.

It began Nov. 24, 1971, when a man calling himself Dan Cooper bought a one-way ticket from Portland to Seattle on Northwest Orient Airlines. Aboard the Boeing 727, he handed a note to the flight attendant saying he had a bomb and that he wanted $200,000 and four parachutes, as well as a refueling truck when the plane reached Seattle.

Once there, he exchanged the passengers for the money and ordered the pilots to take off again with a flight plan for Mexico. Somewhere over Southwest Washington state, the man lowered the rear stair door of the 727 and jumped out. He was never seen again.

The only verified evidence ever found was a small cache of $20 bills discovered along the Columbia River in 1980. They carried serial numbers that matched some of the money given to Cooper. The bulk of what Cooper left behind is in a decades-old cardboard box in the FBI office in downtown Seattle. The boarding pass from the Nov. 24, 1971, Portland-to-Seattle fight bears the name Dan Cooper, handwritten in red ink and all capital letters. They also have a few deteriorated bills and the pink parachute discarded after Cooper cut its strings to secure the money. A padded envelope protects his JCPenney clip-on tie.

In 2016, the FBI announced it would stop actively investigating the case, but would take action on any physical evidence of the either the parachute or the money.

"The mystery surrounding the hijacking of a Northwest Orient Airlines flight in November 1971 by a still-unknown individual resulted in significant international attention and a decades-long manhunt," the FBI said at the time. "Although the FBI appreciated the immense number of tips provided by members of the public, none to date have resulted in a definitive identification of the hijacker."

Sleuths of all kinds have pursued the case over the years, some with theories so wild as to be unbelievable and others with more realistic ideas. Among them, Tom Colbert has been most prominent in recent years (though not the only one to announce a suspect), with his oft-mentioned 40-member cold case team comprised of former FBI, local law enforcement and military personnel.

Colbert has publicly named a U.S. Army veteran, Robert W. Rackstraw, as his Cooper suspect. Rackstraw was actually considered by the FBI in the late 1970s, before the bureau decided he wasn't a match.

But Colbert has over the last seven years crafted a detailed case pointing to Rackstraw, including finding codes in the letters allegedly sent by Cooper to newspapers that further support the veteran as the culprit. Rackstraw, for his part, told the SeattlePI to double check Colbert's story but didn't directly deny the accusation.

Adding to the intrigue of Colbert's story, his team also said the FBI worked to cover up possible leads in the case, starting in the late 1970s, because Rackstraw was in fact a secret CIA operative working all over the globe.

After five decades, the most widely accepted theory is that Cooper died during his escape and his body and belongings are simply lost to the elements. However, FBI agents still get dozens of calls from people either claiming to be Cooper or know information about him every year. Since the 1971 hijacking, the FBI has investigated nearly 1,000 suspects.

Even earlier this year, a local historian led a dig on the banks of the Columbia River with the hope of finding new evidence to crack the case. And while it won't probably be the final word on the Cooper case, it will likely continue what has now become a fantastic local tale.