Artist sketches released by the FBI of D.B. Cooper, who vanished in 1971 with $200,000 in stolen cash after hijacking a commercial airliner. (Handout/Reuters)

They were certain they knew the identity of the long-missing hijacker known as D.B. Cooper, and now the self-appointed investigators wanted their man to turn himself in to the FBI and sign over his life rights for a book and movie project.

The target of their lobbying was Robert “Bob” W. Rackstraw, a Vietnam War veteran who lives in Southern California and had once surfaced briefly as a suspect in the country’s only unsolved hijacking of a commercial airliner.

The FBI announced this month that it was no longer actively pursuing its 45-year-old investigation into the notorious case. But that isn’t likely to deter the people — known as Cooperites — obsessed with finding the folk legend who vanished in 1971 after parachuting out of a plane with $200,000. They attend the Official D.B. Cooper Symposium, pore over Cooper books, trade theories online.

On July 10 and 11, the History Channel aired a two-part documentary chronicling an investigation by a group of Cooperites who set out to prove that Rackstraw, now 72, is D.B. Cooper. The effort was led by Thomas J. Colbert, a Los Angeles-based television and film producer who specializes in developing true-crime and romance stories.

Long before it aired, Colbert and Mark Zaid, a Washington attorney fascinated by the case, tried to persuade Rackstraw to work with them. He could, they told him in a series of emails given to The Washington Post, cash in by confessing that he’s Cooper.

The History Channel's special “D.B. Cooper: Case Closed?” suggests that a 72-year-old California man, Robert W. Rackstraw, might have been the infamous skyjacker known as D.B. Cooper. (The History Channel)

At first, Rackstraw and his longtime defense lawyer, Dennis Roberts, entertained the pitch rather than dismissing it.

“Here is my client’s response to your offer,” Roberts wrote Colbert in May 2013, CC’ing Rackstraw under the email account of “Airbornebob Rackstraw”: “Now, we will consider a real offer if they provide virtually every piece of data and information that they have acquired in the past years (as they claim) subject to our review of the same.”

But the negotiations went nowhere. “I was playing with them,” says Roberts, who also defended Rackstraw four decades ago when he was acquitted on charges of killing his stepfather.

The documentary aired without any formal sit-down with Rackstraw — just an ambush by one of Colbert’s colleagues. During the encounter, Rackstraw describes himself as “old and feeble,” says “I don’t remember any of it,” and drives away.

The segment helped reignite public discussion of the case just as the FBI was packing up its boxes. Even the title tantalized: “D.B. Cooper: Case Closed?”

For the Cooperites, it won’t be closed until they learn the truth.

Lawyer Mark Zaid at his home in the Washington, D.C., region. He was part of an effort to persuade Robert Rackstraw to turn himself into the FBI and sign over his life rights for a movie and book. (Nikki Kahn/The Washington Post)
‘Afraid of heights’

On Nov. 24, 1971, a man who gave the name “Dan Cooper” bought a one-way ticket in Portland, Ore., for a Northwest Orient flight to Seattle. (He became “D.B. Cooper” only after a wire service mistakenly published a story calling him that — and the name stuck.)

He took a seat in the back of the plane and ordered a bourbon and 7-Up. As the plane was taking off, he passed a note to a flight attendant saying he had a bomb and later showed her a nest of wires and red-colored sticks. He demanded $200,000.

When the flight landed in Seattle, Cooper kept most of the crew onboard, but let the 36 passengers go in exchange for the money and parachutes.

Once he got what he needed, Cooper ordered the pilots to take off and head to Mexico City. But somewhere over a southern Washington forest, as the Boeing 727 flew low, the plane’s back staircase deployed. Cooper jumped. Then he and the money disappeared.

The FBI, which never ruled out that the hijacker could have been killed upon landing, interviewed hundreds of people. It never found a body or the parachute. The only lead came in 1980, when a family happened upon $5,800 in cash by the Columbia River whose serial numbers matched the money given to Cooper. His true identity remained a mystery.

Law enforcement officials looked at more than 1,000 suspects, although the FBI wouldn’t confirm or deny that Rackstraw had been one of them.

The bureau’s decision to close its investigation had nothing to do with the History Channel documentary on Rackstraw, said Ayn Dietrich-Williams, a spokeswoman for the FBI Seattle Field Office. It came after a recent round of forensic testing on a different suspect — a man who is no longer alive — failed to show a conclusive link to the skyjacker.

Some of the hijacking suspects became famous, such as Richard Floyd McCoy, because he conducted a similar hijacking less than five months later. But McCoy, a skydiver and Army veteran who was killed by the FBI in a shootout, was dismissed because he didn’t match descriptions given by Northwest Orient’s flight attendants.

Rackstraw, a former Army helicopter pilot who had been awarded a Silver Star for valor, didn’t surface as a suspect until the late 1970s, according to news reports. He’d been arrested on charges of murdering his stepfather, but was acquitted in a trial in 1978.

The following year, he faced charges of aircraft theft, possession of explosives and check fraud, according to news reports. Colbert said Rackstraw was convicted and spent more than a year in jail before being released in 1980. Rackstraw’s attorney said he couldn’t confirm those details. Asked by The Post how the charges were resolved, Rackstraw said, “I was acquitted of everything as I recall.”

Geoffrey Gray, the author of “Skyjack,” the most authoritative history of the Cooper investigation, said Rackstraw was never a serious suspect; he is not mentioned once in Gray’s book.

But Rackstraw seemed to enjoy being identified as a potential hijacking legend.

At one point, a Los Angeles NBC News reporter asked him on camera whether he was Cooper, and Rackstraw gave a cryptic answer: “I’m afraid of heights,” he said, smiling, in the archival footage that Colbert dug up for the documentary. “Could have been. Could have been. I can’t commit myself on something like that.”

‘An act that got out of hand’

Colbert used to ignore the Cooper tips he’d hear all the time as a local CBS journalist in California. But five years ago, a former drug runner told Colbert an incredible tale: The family that discovered the Cooper cash by the Columbia River had actually conspired with a friend of Rackstraw’s to find it, and give the impression that the hijacker drowned.

In 2012, Colbert began assembling a cold-case team of 40 people to examine Rackstraw’s possible role in the hijacking: former FBI officials, a former CIA assistant director, plus Zaid, an attorney who represents intelligence and military officials in security clearance cases and who agreed to work pro bono.

Their target once taught a law course on mediation in 1999 at the University of California at Riverside Extension and then worked at a boat shop.

To get him to talk, Colbert first tried presenting himself as a producer “on the lookout for the next big real-life story” on the Vietnam War, according to emails Colbert gave The Post. He told Rackstraw that he needed veterans as consultants and ultimately asked him to sign a contract for $10,000, and offered much more if he gave away the rights to his personal stories and if their show got produced on television.

Rackstraw asked Colbert whether copyright law would protect any of his information, and how much Colbert would pay him, mentioning he’d been given $1,500 a day to consult on a movie that eventually became the Sylvester Stallone film “Rambo,” according to the emails.

During their discussions, Rackstraw seemed to grow intrigued. He said he’d make a counteroffer, and that he’d want to be the narrator of the movie or television show. Then he backed away.

Colbert, now 59, said he hired a surveillance team to monitor Rackstraw’s movements. In May 2013, he drove to the boat shop Rackstraw worked at and confronted him.

“I said, ‘Bob we know who you are. I have 50 sources saying you’re D.B. Cooper,’ ” Colbert remembered.

Colbert said he urged him to sign away his life rights, predicting he’d earn $1 million through a book and movie deal. Colbert made one other demand: Rackstraw had to turn himself over to the FBI or police. He said he showed Rackstraw two checks already made out to him, each for $10,000 for the purpose of optioning his life rights. But Rackstraw didn’t take them.

Colbert ramped up the pressure through email.

“Airborne Bob,” Colbert wrote, using Rackstraw’s email account name. “If you don’t respond, [the media will] go hunt down your relatives. I’m afraid this will be the Rackstraw clan’s new life. But it doesn’t have to be. It’s not too late to . . . receive my hefty option fee, and tell us the truth about Nov. 24 1971 — one time, in a private controlled setting. Then, by next year, you’ll be sharing the profits (6-7 figures) from my best-selling book and hit movie.”

Rackstraw’s attorney replied, demanding all the evidence Colbert had collected before considering a deal.

Among other pieces of circumstantial evidence, Colbert touted eyewitnesses who allegedly put Rackstraw in Oregon months before the hijacking, living under a fake name and suddenly vanishing in November, five days before the flight.

“Thanks for some very helpful information — most of which I didn’t know,” Roberts told him. “I will be in touch with Airborne Bob [why does this sound like some cold remedy that never works for me] and get back to you.”

But Roberts said he had no intention of letting Rackstraw get involved with the documentary.

“I know [Rackstraw] is not D.B. Cooper and it pissed me off that they were torturing Bob’s friends” by trying to interview them, he explained. “All these people close to him are thinking, ‘Geez, maybe these guys are right?’ They now start looking at Bob with a jaundiced eye. It’s awful. It’s truly awful.”

By October 2013, Roberts wasn’t playing around anymore.

“For the record,” he told Zaid in an email, “Mr. Rackstraw is NOT D.B. Cooper and has never claimed to be.”

Roberts threatened to file a lawsuit against “whoever plans to broadcast this false and defamatory accusation.” About a week later, Roberts wrote Zaid again, saying: “Between us Bobby always enjoyed letting people think he is D.B. Cooper,” mostly to appeal to women. “[B]ut from everything I know it is an act that got out of hand. Well, anyway you’ll find out soon enough.”

‘A victim and suspect’

Rackstraw watched the documentary, he said in an interview.

He watched himself being ambushed. He watched the man whose son found the ransom money along the Columbia River deny that it had been planted there. He watched a Northwest Orient flight attendant examine an old photo of him and his decades-old NBC interview and repeatedly say she didn’t think he was the hijacker. He watched Curtis Eng, the FBI’s special agent in charge of the Cooper investigation, say he wasn’t convinced that Colbert’s team had cracked the case.

Asked by The Post if he’s D.B. Cooper, Rackstraw refused to answer. He described himself as a “homeless, disabled veteran” and said he’s working on his own book and film about his life.

“Watch the movie,” he said, before adding: “It’s been asked for 45 years. I was never charged. I was made a victim and suspect and holy hell was raised throughout my life.”

He said the documentary defamed him and that he was planning on suing the network, Colbert and others involved in the project, which also included a book called “The Last Master Outlaw.”

A History Channel publicist declined to comment. But Zaid said he’d welcome the lawsuit.

“I would love it,” Zaid said. “It would give me every legal tool at my disposal to break this case wide open.”