Detailed Instructions: In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.
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 To ensure delivery to your inbox, please add us to your address book. ||||| The FBI has put a halt to one of its most famous — and frustrating — manhunts. 
  
 The lone agent assigned to the D.B. Cooper manhunt was assigned to other mysteries within the federal agency on Friday, effectively shuttering the 45-year-old case after the FBI — and troves of tipsters — failed to identity the infamous hijacker, the FBI announced. 
  
 “Unfortunately, none of the well-meaning tips or applications of new investigative technology have yielded the necessary proof,” FBI spokeswoman Ayn Dietrich-Williams said in a statement late Monday. 
  
 The agency has poured over the legendary theft ever since a frigid night on Nov. 24, 1971, when a man calling himself Dan Cooper flashed what appeared to be a bomb and hijacked a passenger plane from Oregon to Seattle. 
  
 Man who packed parachutes for ‘71 skyjacker D.B. Cooper killed in Seattle 
  
 Ultimately, he freed the 36 passengers in exchange for $200,000 in cash and four parachutes before leaping from the Northwest Orient Airlines plane — and was never seen again. 
  
 The 1973 sketching of what witnesses said the passenger known as D.B. Cooper looked like before he leaped from a passenger plane with $200,000 in stolen cash. (AP) 
  
 Four decades later, Cooper essentially got away with the nearly perfect crime, but the dead-end investigation has only ballooned with new and troubling questions. 
  
 Former case agent Larry Carr questioned whether the sky pirate actually survived the plunge into southwest Washington near the state border with Oregon. 
  
 He also leaned on internet sleuthers who pointed Carr to a French-language comic book series based on a fictional paratrooper named “Dan Cooper” that may have inspired a fake identity. 
  
 Missing Malaysia Airlines plane sparks conspiracy theories 
  
 The current Cooper investigator with the FBI’s violent crimes squad had no luck pinning down a credible lead after taking over for Carr. 
  
 Badly decomposed $20 bills found along the Columbia River will be stored at FBI Headquarters in Washington D.C. after the FBI closed the Cooper case. (Bettmann Archive) 
  
 The case inspired decades of amateur investigations, but none, regardless of their credibly, “resulted in a definitive identification of the hijacker,” Dietrich-Williams said. 
  
 “The FBI exhaustively reviewed all credible leads,” she added. 
  
 Some of the zaniest of theories nixed by federal authorities was a man on his deathbed bragging that he was the famed hijacker while several relatives claimed their loved one was Cooper. A man believed his deceased World War II veteran brother — a former paratrooper named Kenneth Christensen — may have died withholding his secret Cooper past while a woman suspected her uncle, Lynn Doyle Cooper, may have been Cooper. 
  
 He was ruled out after investigators realized his DNA did not match what was found on a black tie. 
  
 FBI agents dig for money from the Cooper case on a beach on the north shore of the Columbia River. (Bettmann Archive/Getty) 
  
 As for the aging evidence collected over the years — including the snippets of weathered $20 bills an 8-year-old boy found along the Columbia River in 1980 — the FBI will keep it filed away at its headquarters in Washington D.C. 
  
 A pink-hued parachute and the black tie are also among the physical clues collected by investigators. 
  
 Although the FBI will no longer actively investigate the case, Dietrich-Williams said the agency will continue to field tips related to the parachute and stolen cash. 
  
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 With Denis Slattery ||||| A Santa Cruz Sentinel story from 1978 describes a mayday call over Monterey Bay. (Santa Cruz Sentinel archives) 
  
 SCOTTS VALLEY >> A group of retired FBI investigators have linked a Scotts Valley native to a 1971 plane hijacking case that has flummoxed authorities for decades. 
  
 A two-part, four-hour special on The History Channel called “D.B. Cooper: Case Closed?” aired on Sunday and Monday nights, and a book titled “The Last Master Outlaw” will be released Tuesday. Episodes are online at History.com/shows/d-b-cooper-case-closed. 
  
 The story centers on Robert Wesley Rackstraw, who is now 72 and grew up in Scotts Valley. A team of retired investigators, including former FBI agents, believes he is the man of many aliases who became known as D.B. Cooper. 
  
 Cooper famously hijacked a commercial plane headed from Portland to Seattle in 1971 by claiming that he had dynamite on him. He ordered the pilot to land the plane so he could collect a $200,000 ransom from authorities. He then ordered the pilot to fly to Mexico and parachuted out of the plane into an icy rainstorm above Oregon. 
  
 Authorities believed the skyjacker could not have survived the fall. Others believed he survived and went on to commit other “skyjackings.” Rackstraw now lives on a boat in San Diego County, said Thomas Colbert, a co-author of the book and a consulting executive director of the History Channel program. 
  
 “He’s off-the-books genius. He’s a master criminal,” Colbert said Monday. “It’s going to stun your town.” 
  
 Rackstraw grew up in a “very poor family” in a two-bedroom house on a creek in Scotts Valley in the 1960s, Colbert said. Rackstraw graduated from Santa Cruz High School, joined the Army and served on a helicopter crew and other units during the Vietnam War. 
  
 He was discharged in 1971 and started to fly small planes for a real estate development company in Washington and elsewhere in the Pacific Northwest. 
  
 Seven years after the Oregon skyjacker case, Rackstraw tried to fake his death by bailing out of a plane over Monterey Bay, Colbert said. An Oct. 16, 1978 story in the Sentinel described the pilot’s mayday call and a Coast Guard search. Authorities later said it was a hoax. 
  
 Around that time, Rackstraw went missing from his ex-wife and children in Stockton. 
  
 “The children hadn’t seen their daddy in one year, and when the doorbell rang it was the FBI looking for him,” Colbert said. “This guy is connected to 60 towns in 28 states, six careers, three families and so far, 16 identities.” 
  
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 Rackstraw’s past included an arrest on suspicion of possession of explosives and writing about $75,000 worth of bad checks, authorities said. In February 1978, months before the mayday call, authorities found Rackstraw in Iran and deported him to New York City. 
  
 These days, Rackstraw lives a quiet life aboard the 45-foot cruiser “Poverty Sucks” in a yacht harbor in San Diego Bay. In the History Channel program, Rackstraw denies being D.B. Cooper. 
  
 “He’s not D.B. Cooper,” said Rackstraw’s 78-year-old Oakland attorney, Dennis Roberts, on Monday. “Everything I’ve heard is that D.B. Cooper died, and he (Rackstraw) is alive.” 
  
 Roberts said that Rackstraw might have casually boasted that he was Cooper over the years because of his military career. Yet Roberts said that Rackstraw did not have the skills to parachute into an icy storm and survive. 
  
 Roberts said he’s considering filing a civil suit against the History Channel and the book’s authors, although he said he has not yet seen the programs nor read the book. 
  
 Colbert said he and a group of 12 former FBI agents researched and fact-checked the case for five years. At least one current FBI agent said he too believes Rackstraw is D.B. Cooper. Yet he likely will not be brought to trial. 
  
 “A former FBI assistant director, acting as a liaison for History Channel, said the bureau has serious concerns on the feasibility of a criminal prosecution 45 years after the crime,” Colbert said. “While it wasn’t ‘unsolvable,’ special agents now fear it is ‘unprosecutable’ based on just circumstantial evidence.” ||||| 0 D.B. Cooper case no longer actively investigated by FBI 
  
 The D.B. Cooper case, regarding the 1971 hijacking of a Boeing jet from Portland to Seattle that is the only unsolved case of its kind, is no longer being actively investigated by the FBI, a spokeswoman announced Monday night. 
  
 "Following one of the longest and most exhaustive investigations in our history, on July 8, 2016, the FBI redirected resources allocated to the 'DB Cooper' case, in order to focus on other investigative priorities," spokeswoman Ayn Dietrich-Williams said. 
  
 "During the course of the 45-year NORJAK investigation, the FBI exhaustively reviewed all credible leads, coordinated between multiple field offices to conduct searches, collected all available evidence, and interviewed all identified witnesses. Over the years, the FBI has applied numerous new and innovative investigative techniques, as well as examined countless items at the FBI Laboratory. Evidence obtained during the course of the investigation will now be preserved for historical purposes at FBI headquarters in Washington, D.C. 
  
 PHOTOS: D.B. Cooper hijacking 
  
 "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. 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. The tips have conveyed plausible theories, descriptive information about individuals potentially matching the hijacker, and anecdotes—to include accounts of sudden, unexplained wealth." 
  
 The FBI indicated it would be difficult to solve the case. 
  
 "In order to solve a case, the FBI must prove culpability beyond a reasonable doubt, and, unfortunately, none of the well-meaning tips or applications of new investigative technology have yielded the necessary proof," Dietrich-Williams said. "Every time the FBI assesses additional tips for the NORJAK case, investigative resources and manpower are diverted from programs that more urgently need attention. 
  
 "Although the FBI will no longer actively investigate this case, should specific physical evidence emerge—related specifically to the parachutes or the money taken by the hijacker—individuals with those materials are asked to contact their local FBI field office." 
  
 © 2018 Cox Media Group. |||||
A:
Well, Mr. Cooper, or whatever your name is, you've officially stumped the FBI. The agency announced Monday that it was no longer investigating the famous 1971 hijacking in which a passenger known as DB Cooper jumped out of a plane over Washington state with a parachute and $200,000 in cash, reports KIRO in Seattle. It is the only such unsolved hijacking in US history, and it appears that it will stay that way. "Following one of the longest and most exhaustive investigations in our history, on July 8, 2016, the FBI redirected resources allocated to the 'DB Cooper' case, in order to focus on other investigative priorities," says an FBI spokeswoman. It's not clear what prompted the FBI statement, but it comes just after a documentary aired on the History Channel in which former FBI detectives claimed to have cracked the case. They name 72-year-old Robert Rackstraw, who now lives on a boat in a yacht harbor in San Diego Bay, reports the Monterey Herald. Rackstraw—who allegedly tried to fake his own death in 1978 by, yes, bailing out of a plane—denies the allegations through his attorney. "He's not DB Cooper," says the lawyer, though he acknowledges that his client may have floated the claim himself over the years. Of course, this isn't the first DB Cooper theory and probably won't be the last. Some think Cooper never survived the jump, pointing to the discovery of some of the cash by the Columbia River in 1980, notes the New York Daily News. But "the FBI exhaustively reviewed all credible leads," says the FBI spokeswoman. Still, she adds, if hard evidence emerges, investigators would be back on the job. (Another theory suggests Cooper was a grocery store manager from Michigan.)