PORTLAND, Ore. (KOIN) – During a new search effort last week, amateur investigators claim they found a flat sheet, which they believe was used by an escaped plane hijacker in 1971.

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The mystery of D.B. Cooper’s true identity and what happened after he dropped out of the rear of a Boeing 727 on Nov. 24, 1971, the night before Thanksgiving, has become a decadeslong source of popular interest.

Cooper bought a $20 ticket from Portland, Oregon, to Seattle-Tacoma International Airport under the name “Dan Cooper,” but a mix-up in an early report about the “skyjacking” dubbed him D.B., and the name stuck, according to the Associated Press. Cooper, who wore dark sunglasses and a business suit, gave a note to a flight attendant just after takeoff that read, “Miss, I have a bomb and would like you to sit by me.”

His demands included four parachutes and $200,000 cash, which he received after the plane touched down at Sea-Tac to allow the rest of the passengers and a couple of flight attendants to get off. The plane took off, headed toward Reno, Nevada when he jumped somewhere over southwestern Washington.

While Cooper was never found, his parachute and some of the money tied to him were discovered later.

Eric Ulis has been investigating the D.B. Cooper case and recently led a small team as they searched a “treacherous” tree-and blackberry-lined trench, where they believed the hijacker’s parachute may have been dumped.

The Vancouver trench was previously unsearched and is one mile from where a portion of D.B. Cooper’s ransom was found in 1980, Ulis said.

On the first day of the latest search, the group found a tattered white sheet, seen below, which they believe was bought from Kmart between 1964 and 1967. Ulis says an analysis of the sheet’s fibers will be conducted to determine whether they resemble fibers found on Cooper’s clip-on tie, which he said was bought from JC Penney in 1964 or 1965.

  • Amateur DB Cooper investigators reveal find in latest Vancouver, WA search
  • Amateur DB Cooper investigators reveal find in latest Vancouver, WA search
  • Amateur DB Cooper investigators reveal find in latest Vancouver, WA search
  • Amateur DB Cooper investigators reveal find in latest Vancouver, WA search
  • Amateur DB Cooper investigators reveal find in latest Vancouver, WA search

Ulis pointed to witness statements from Flight Attendant Tina Mucklow who claims she saw Cooper try to wrap the ransom in a “white material,” and other witnesses who saw Cooper carrying a paper bag with unknown contents onto the plane.

“Given the flight attendant account of seeing Cooper use a white material to wrap the $200,000 ransom, the mystery of the paper bag, the age of the white flat sheet, and the location of its discovery, the possibilities cannot be ignored,” Ulis said. “This item is at least 56-years old and was transported to the difficult-to-reach spot, within ½ mile of the 1980 money find, somehow, for some reason, by someone.”

Ulis said the sheet will be displayed at CooperCon 2023 in Seattle.

The search comes after Ulis claimed new information was revealed by the Seattle air traffic controller who managed the skyjacked Northwest Orient Flight 305, two US Air Force F-106 chase jets, and an Oregon Air National Guard T-33 during the 1971 skyjacking.

“It is clear to me that DB Cooper actually landed much closer to the 1980 money find spot than originally believed,” Ulis said. “I am absolutely certain that the heavy parachute DB Cooper jumped with is still near where the man landed 52 years ago.”

Jeremy Tanner and KOIN’s Dan Tilkin contributed to this report.