After an exhaustive 45-year investigation, the FBI in 2016 finally called off its official search for D.B. Cooper, the mysterious man who, on Nov. 24, 1971, hijacked a plane headed from Portland, Oregon to Seattle, Washington. In one of the most daring and unforgettable crimes in aviation history, he parachuted from the Boeing 727 with $200,000 in ransom money, eluding capture and enrapturing amateur sleuths worldwide.

In the decades that followed the brazen act, the bureau eliminated all but two of 1,000 suspects in the case. The most substantive leads included $5,800 of the ransom money found by a boy in 1980 along the Columbia River in Washington state, and taunting letters received by several U.S. newspapers. The letters, in particular, have offered tantalizing clues to the identity of the man behind the alias who got away with what would have been $1.2 million today.

At least six letters—typed, handwritten and made using ransom-style cut out letters—were sent to several newspapers soon after the hijacking, all claiming to be from Cooper. The FBI considered most to be hoaxes. But intriguingly, they held back the last two letters from the public until the 2000s, which may indicate they took those far more seriously.

A first letter, signed “DB Cooper” and sent from Oakdale, California to the Reno Evening Gazette, was received on November 29, 1971. Using letters cut and paste from a Sacramento Bee newspaper, it read: “Attention! Thanks for the hospitality. Was in a rut.”

A second letter, handwritten and signed “D.B. Cooper,” was postmarked November 30, 1971 and sent to the Vancouver Province in British Columbia with the following message:

"The composite drawing on Page 3 as suspected by the FBI does not represent the truth.

"I enjoyed the Grey Cup game. Am leaving Vancouver.

"Thanks for the hospitality."

A third letter, mailed in northern Oregon on December 1, 1971, was received by the Portland Oregonian. Using letters cut from a Playboy magazine, it read, “Am alive and doing well in hometown. P.O. The system that beats the system.”

Letter number four, received by the Reno Evening Gazette, was also mailed on December 1 (but from the Sacramento, California area). Pasted from letters, it read, “Plan ahead for retirement income” and was signed “D.B. Cooper.”

A fifth letter, signed “D.B. Cooper” and brimming with taunts, was postmarked December 11, 1971, and sent to The New York Times, Seattle Times, Los Angeles Times and The Washington Post. The FBI released its contents after a private investigative team led by documentary filmmaker Thomas Colbert filed a Freedom of Information Act request.

"Sirs, I knew from the start that I wouldn't be caught,” the letter read. “I didn't rob Northwest Orient because I thought it would be romantic, heroic or any of the other euphemisms that seem to attach to situations of high risks. I'm no modern day Robin Hood. Unfortunately I do have only 14 months to live.

“My life has been one of hate, turmoil, hunger and more hate; this seemed to be the fastest and most profitable way to gain a few fast grains of peace of mind. I don't blame people for hating me for what I've done nor do I blame anybody for wanting me to be caught and punished, though this can never happen. Here are some (not all) of the things working against the authorities:

I'm not a boasting man

I left no fingerprints

I wore a toupee

I wore putty make-up

“They could add or subtract from the composite a hundred times and not come up with an accurate description; and we both know it. I've come and gone on several airline flights already and am not holed up in some obscure backwoods town. Neither am I a psychopathic (sic) killer. As a matter of fact I've never even received a speeding ticket.

Thank you for your attention."

Colbert’s team found codes in the fifth and sixth letters, including the numbers "717171684*," which they deciphered as “I’m LT Robert W. Rackstraw.” Rackstraw, a Vietnam War vet and former U.S. paratrooper who died in 2019, both denied and refused to discount himself as being the infamous skyjacker, according to the Oregonian. The FBI investigated—and cleared—Rackstraw in the late 1970s.

A sixth letter, mailed March 28, 1972, from Jacksonville, Florida to the Portland Oregonian and signed “A Rich Man,” read: “This letter is too (sic) let you know I am not dead but really alive and just back from the Bahamas, so your silly troopers up there can stop looking for me. That is just how dumb this government is. I like your articles about me but you can stop them now, D.B. Cooper is not real.

“I had to do something with the experience Uncle taught me, so here I am, a very rich man. Uncle gave too much of it to world idiots and no work for me. I had to do it to relieve myself of frustration. I want out of the system and saw a way through good ole Unk. Now you know. I am going around the world and they will never find me because I am smarter than the system's lackey cops and lame-duck leaders. Now it is Uncle's turn to weep and pay one of it's own some cash for a change. (And please tell the lackey cops D.B. Cooper is not my real name).”

Again, Colbert’s team says this letter is coded to say, "I'm LT Robert W. Rackstraw, D.B. Cooper is not my real name" and "I want out of the system and saw a way by hijacking one jet plane."

But the identity of Cooper—and the author or authors of the letters—officially remains a mystery. FBI spokeswoman Ayn Sandalo Dietrich told the Reno Gazette Journal in 2014 that the letters were sent to the FBI laboratory in Washington, D.C. for analysis, but nothing was found: "It was never proven if the actual hijacker wrote the letters."