Dan Cooper, best known as D. B. Cooper, was the alias of an unidentified man who hijacked Northwest Orient Airlines Flight 305, a Boeing 727 aircraft flying from Portland, Oregon, to Seattle, Washington, on November 24, 1971. Cooper told the flight crew he had a bomb and demanded $200,000 in ransom (equivalent to $1,600,000 in 2025) and four parachutes upon landing in Seattle. After releasing the passengers in Seattle, Cooper directed the crew to refuel the aircraft and begin a second flight to Mexico City, with a refueling stop in Reno, Nevada. After taking off from Seattle, Cooper opened the aircraft's aft door, deployed the airstair, and parachuted to an uncertain fate over a remote, heavily wooded area of Southwest Washington. Because of a reporter's error, the aircraft hijacker became known as D. B. Cooper; the hijacker's true identity and fate remain unknown.

In 1980, a small portion of the ransom money ($5,800) was found along the banks of the Columbia River near Vancouver, Washington. The discovery of the money renewed public interest in the crime but yielded no additional information, and the remaining money was never recovered. For 45 years after the hijacking, the Federal Bureau of Investigation (FBI) maintained an active investigation and built an extensive case file but did not reach any definitive conclusions about Cooper's identity. The FBI officially suspended active investigation of the case in 2016, although journalists, professional investigators, and amateur sleuths continue to pursue numerous theories for Cooper's identity and ultimate fate.

Cooper's hijacking—and several imitators (known as the D. B. Cooper copycat hijackings) in the year after—prompted immediate and major upgrades to security measures for airports and commercial aviation. Metal detectors were installed at airports, baggage inspection became mandatory, and passengers who paid cash for tickets on the day of departure were selected for additional scrutiny. The Cooper hijacking remains the only documented unsolved case of air piracy in the history of commercial aviation.

Northwest Orient Airlines Flight 305

N467US, the aircraft involved in the hijacking, seen in 1972
Hijacking
Date	November 24, 1971
Summary	Hijacking and extortion
Site	Between Portland, Oregon, U.S., and Seattle, Washington, U.S.
Aircraft
Aircraft type	Boeing 727-51
Operator	Northwest Orient Airlines
Call sign	NORTHWEST 305
Registration	N467US
Flight origin	Portland International Airport
Destination	Seattle–Tacoma International Airport
Occupants	42 (including hijacker)
Passengers	36 (including hijacker)
Crew	6
Missing	1 (hijacker)
Survivors	41

On November 24, 1971 (Thanksgiving Eve), a man approached the flight counter for Northwest Orient Airlines at Portland International Airport. Using cash,^[1] the man bought a one-way ticket on Flight 305, a 30-minute trip north to Seattle–Tacoma International Airport (Sea-Tac). On his ticket, the man listed his name as "Dan Cooper". Eyewitnesses described Cooper as a white male in his mid-40s, with dark hair and brown eyes, wearing a black or brown business suit, a white shirt, a thin black tie, a black raincoat, and brown shoes.^{[1][2]: 294} Carrying a black attaché case and a brown paper bag,^[2]: 294 Cooper boarded Flight 305, a Boeing 727-100 (FAA registration N467US). Cooper took seat 18-E in the last row and ordered a drink, a bourbon and 7-Up, from a flight attendant.^[3][4]

Including Cooper, Flight 305 had 36 passengers aboard and a crew of six: Captain William A. Scott, First Officer William "Bill" J. Rataczak, flight engineer Harold E. Anderson, and flight attendants Alice Hancock, Tina Mucklow and Florence Schaffner. Flight 305 left Portland on schedule at 2:50 pm PST.^[5][6] Shortly after takeoff, Cooper handed a note to flight attendant Schaffner, who was sitting in the jump seat at the rear of the airplane,^[7]: 159 directly behind Cooper. Assuming the note was a lonely businessman's telephone number, Schaffner dropped the note unopened into her purse.^[8] Cooper then leaned toward her and whispered, "Miss, you'd better look at that note. I have a bomb."^[9]

Schaffner opened the note. In neat, all-capital letters printed with a felt-tip pen,^[10] Cooper had written, "Miss—I have a bomb in my briefcase and want you to sit by me."^[11] Schaffner returned the note to Cooper,^[12] sat down as he requested, and asked quietly to see the bomb. Cooper opened his attaché case, and Schaffner saw what appeared to be a bomb: a large cylindrical battery attached with wires to two rows of four red cylinders she assumed were dynamite.^[13][14]

Cooper closed the briefcase and told Schaffner his demands. Schaffner wrote a note with Cooper's demands, brought it to the cockpit, and informed the flight crew of the situation. Captain Scott directed Schaffner to remain in the cockpit for the remainder of the flight and take notes of events as they happened.^[11] He then relayed to Northwest flight operations in Minnesota the hijacker's demands: "[Cooper] requests $200,000 in a knapsack by 5:00 pm. He wants two front parachutes, two back parachutes. He wants the money in negotiable American currency."^[15][a] By requesting two sets of parachutes, Cooper implied he planned to take a hostage with him, thereby discouraging authorities from supplying non-functional equipment.^[16]

With Schaffner in the cockpit, flight attendant Mucklow sat next to Cooper to act as a liaison between him and the flight crew.^{[17][7]: 160} Cooper made additional demands through Mucklow: upon landing at Sea-Tac, fuel trucks must meet the plane, and all passengers must remain seated while Mucklow brought the money aboard the plane. Cooper said he would release the passengers after he had the money. The last items brought aboard would be the four parachutes.^[7]: 160

Scott informed Sea–Tac air traffic control of the situation, who contacted the Seattle Police Department (SPD) and the Federal Bureau of Investigation (FBI). The passengers were told their arrival in Seattle would be delayed because of a "minor mechanical difficulty".^[18] Donald Nyrop, the president of Northwest at the time, authorized payment of the ransom and ordered all employees to cooperate with the hijacker and comply with his demands.^[19] For approximately two hours, Flight 305 circled Puget Sound in a holding pattern to give the SPD and the FBI sufficient time to assemble Cooper's ransom money and parachutes, and to mobilize emergency personnel.^[20]

On board the aircraft, Cooper demanded Mucklow remain by his side at all times.^[7]: 150 Mucklow later said Cooper appeared familiar with the local terrain; while looking out the window, he remarked, "Looks like Tacoma down there", as the aircraft flew above it. When Mucklow told Cooper the parachutes were coming from McChord Air Force Base, Cooper correctly noted McChord was only a 20-minute drive from Sea-Tac.^[7]: 156 She later described the hijacker's demeanor: "[Cooper] was not nervous. He seemed rather nice and he was not cruel or nasty."^[21]: 174

While the aircraft continued circling Seattle, Mucklow chatted with Cooper and asked why he chose Northwest Airlines to hijack. Cooper laughed and said, "It's not because I have a grudge against your airline, it's just because I have a grudge", before he explained the flight simply suited his needs.^[7]: 161 Cooper asked where Mucklow was from; she answered she was originally from Pennsylvania but was living in Minneapolis at the time. Cooper responded Minnesota was "very nice country."^[7]: 161 Mucklow asked where Cooper was from but he became upset and refused to answer.^[7]: 160 Cooper asked Mucklow if she smoked and offered her a cigarette. Mucklow replied she had quit but accepted the cigarette.^[7]: 161

FBI records note Cooper spoke briefly to an unidentified passenger while the aircraft maintained its holding pattern over Seattle. In his interview with FBI agents, passenger George Labissoniere stated he visited the restroom directly behind Cooper on several occasions. After one visit, Labissoniere said the path to his seat was blocked by a passenger wearing a cowboy hat, who was questioning Mucklow about the supposed mechanical problem delaying them. Labissoniere said Cooper was initially amused by the interaction, then became irritated and told the man to return to his seat, but "the cowboy" ignored Cooper and continued to question Mucklow. Labissoniere claimed he eventually persuaded "the cowboy" to return to his seat.^[22]: 170

Mucklow's version of the interaction differed from Labissoniere's. She said a passenger approached her and asked for a sports magazine to read because he was bored. She and the passenger moved to an area directly behind Cooper, where they both looked for magazines. The passenger took a copy of The New Yorker and returned to his seat. When Mucklow returned to sit with Cooper, he said, "If that is a sky marshal, I don't want any more of that," but Mucklow reassured Cooper no sky marshals were on the flight.^[7]: 161 Despite his brief interaction with Cooper, "the cowboy" was not interviewed by the FBI and was never identified.^[23]

The $200,000 ransom was received from Seattle First National Bank in a bag weighing approximately 19 pounds (8.5 kg).^[24]: 123 This was because the ransom money was made of 10,000 unmarked $20 bills, as Cooper had specifically requested.^[25] The money, most of which had serial numbers beginning with "L" and thus indicated issuance by the Federal Reserve Bank of San Francisco,^[26] was photographed on microfilm by the FBI.^[22]: 101 The SPD obtained the two front (reserve) parachutes from a local skydiving school, and the two back (main) parachutes from a local stunt pilot.^[27]

Around 5:24 PST, Captain Scott was informed the parachutes had been delivered to Sea-Tac and notified Cooper they would be landing soon. At 5:46 PST, Flight 305 landed at Sea-Tac.^[7]: 163 With Cooper's permission, Scott parked the aircraft on a partially lit runway, away from the main terminal.^[7]: 163 Cooper demanded only one representative of the airline approach the plane with the parachutes and money, and the only entrance and exit would be through the aircraft's front door via boarding stairs.^[28]: 15

Northwest's Seattle operations manager, Al Lee, was designated to be the courier. To avoid the possibility Cooper might mistake Lee's airline uniform for a law enforcement officer, he changed into civilian clothes for the task.^[29] With the passengers remaining seated, a ground crew attached a boarding stair. Per Cooper's directive, Mucklow exited the aircraft through the front door and retrieved the bag containing the ransom money. When she returned, she carried the bag past the seated passengers to Cooper in the last row.^{[30][7]: 163}

Cooper then agreed to release the passengers.^[4] As they disembarked, Cooper inspected the money. In an attempt to break the tension, Mucklow jokingly asked Cooper if she could have some of it. Cooper readily agreed and handed her a packet of bills, but she immediately returned the money and explained accepting gratuities was against company policy. She said Cooper had tried to tip her and the other two flight attendants earlier in the flight with money from his pocket, but they had each declined, citing the policy.^[7]: 152

With the passengers safely disembarked, only Cooper and the six crew members remained aboard.^[7]: 153 In accordance with his demands, Mucklow made three trips outside the aircraft to retrieve the parachutes, which she brought to him in the rear of the plane.^{[7]: 152–153} While Mucklow brought aboard the parachutes, Schaffner asked Cooper if she could retrieve her purse, stored in a compartment behind his seat. Cooper agreed and told her he would not bite her.^[7]: 163 Flight attendant Hancock then asked Cooper if the flight attendants could leave, to which he replied, "Whatever you girls would like",^{[7]: 163 [31]} so Hancock and Schaffner disembarked. When Mucklow brought the final parachute to Cooper, she gave him printed instructions for using the parachutes, but Cooper said he did not need them.^[7]: 163

A problem with the refueling process caused a delay, so a second truck and then a third were brought to the aircraft to complete the refueling.^[32] During the delay, Mucklow said Cooper complained the money was delivered in a cloth bag instead of a knapsack as he had directed, and he now had to improvise a new way to transport the money.^[7]: 163 Using a pocket knife, he cut the canopy from one of the reserve parachutes, and stuffed some of the money into the empty parachute bag.^[7]: 155

A Federal Aviation Administration (FAA) official requested a face-to-face meeting with Cooper aboard the aircraft, but Cooper denied the request.^[33] Cooper became impatient, saying, "This shouldn't take so long...let's get this show on the road."^[34][35] Cooper then gave the cockpit crew his flight plan and directives: a southeast course toward Mexico City at the minimum airspeed possible without stalling the aircraft—approximately 100 knots (185 km/h; 115 mph)—at a maximum 10,000-foot (3,000 m) altitude. Cooper also instructed Rataczak to keep the landing gear deployed, lower the wing flaps to 15°, and leave the cabin unpressurized.^[36]

First Officer Rataczak informed Cooper the configuration limited the aircraft's range to about 1,000 miles (1,600 km), so a second refueling would be necessary before entering Mexico. Cooper and the crew discussed options, agreeing on Reno–Tahoe International Airport as the refueling stop.^[37][38] Cooper further directed the aircraft take off with the aft exit door open and its airstair extended.^[39] Northwest officials objected for reasons of safety, but Cooper countered by saying, "It can be done, do it." However, Cooper relented and said he would lower the airstair himself once they were airborne.^[39] Cooper demanded Mucklow remain aboard to assist the operation.^[7]: 153

Around 7:40 pm, Flight 305 took off, with only Cooper, Mucklow, Scott, Rataczak and flight engineer Anderson aboard.^[40] Two F-106 fighters from McChord Air Force Base,^[41] plus a Lockheed T-33 trainer—diverted from an unrelated Air National Guard mission—followed the 727. All three jets maintained "S" flight patterns to stay behind the slow-moving 727,^[21]: 141 and out of Cooper's view. After takeoff, Cooper instructed Mucklow to lower the aft airstair. Mucklow told him and the flight crew she feared being sucked out of the aircraft.^[7]: 156

The flight crew suggested Mucklow come to the cockpit and retrieve an emergency rope with which she could tie herself to a seat. Cooper rejected the suggestion, stating he did not want her going up front or the flight crew coming back to the cabin.^[7]: 164 Mucklow continued to express her fear to Cooper, and asked him to cut some cord from one of the parachutes to create a safety line for her. Cooper said he would lower the airstair,^[7]: 164 instructed her to go to the cockpit, close the curtain partition between the coach and first class sections and not return.^[7]: 156

Before she left, Mucklow begged Cooper, "Please, please take the bomb with you."^[17] Cooper replied he would either disarm it or take it with him.^[7]: 164 As Mucklow walked to the cockpit and turned to close the curtain partition, she saw Cooper standing in the aisle tying what appeared to be the money bag around his waist.^{[42][7]: 164} From takeoff to when Mucklow entered the cockpit, four to five minutes had elapsed. For the rest of the flight to Reno, Mucklow remained in the cockpit,^[7]: 164 and was the last person to see Cooper. Around 8:00 pm, a cockpit warning light flashed, indicating the airstair had been deployed. Scott and Rataczak used the plane's intercom to ask Cooper if he needed assistance, but Cooper declined.^[43][35] The crew's ears popped from the drop in air pressure from the aft exit door being opened.^[44] At approximately 8:13 p.m., the aircraft's tail section suddenly pitched upward, forcing the pilots to trim and return the aircraft to level flight.^[45] In his interview with the FBI, Rataczak said the sudden upward pitch occurred while the flight was near Portland's northern suburbs.^[7]: 322

With the aft exit door open and its airstair deployed, the flight crew remained in the cockpit, unsure if Cooper was still aboard. Mucklow used the intercom to inform Cooper they were approaching Reno and he needed to raise the airstair so the airplane could land safely. She repeated her requests as the pilots made the final approach to land, but neither Mucklow nor the flight crew received a reply from Cooper.^[7]: 164 At 11:02 pm, with the airstair still deployed, Flight 305 landed at Reno–Tahoe International Airport.^[46] FBI agents, state troopers, sheriff's deputies, and Reno police established a perimeter around the aircraft; fearing the hijacker and the bomb were still aboard, they did not approach the plane. Scott searched the cabin and confirmed Cooper was no longer aboard. After a 30-minute search, an FBI bomb squad declared the cabin safe.^[47]

In addition to 66 latent fingerprints aboard the plane,^[48] FBI agents recovered Cooper's black clip-on tie, tie clip and two of the four parachutes,^[a] one of which had been opened and had three shroud lines cut from the canopy.^{[49][new archival link needed]} Investigators interviewed eyewitnesses in Portland, Seattle and Reno, and developed a series of composite sketches.^[50] Local and federal authorities immediately began questioning possible suspects.^[1] In a rush to meet a deadline, reporter James Long of The Oregon Journal recorded the name "Dan Cooper" as "D. B. Cooper".^[51][52] United Press International wire service reporter Clyde Jabin republished Long's error,^[53][54] and as other media outlets repeated the error,^[55][56] the name "D. B. Cooper" stuck.^[45]

Acting on the possibility the hijacker may have used his real name (or the same alias in a previous crime), Portland police discovered and interviewed a local resident named D. B. Cooper. The Portland Cooper had a minor police record but was quickly eliminated as a suspect. Due to the number of variables and parameters, precisely defining the area to search was difficult. The 727's airspeed estimates varied, the environmental conditions along the flight path varied with the aircraft's location and altitude,^[7]: 300 and only Cooper knew how long he remained in free fall before pulling his ripcord.^[35] The F-106 pilots neither saw anyone jumping from the airliner nor did their radar detect a deployed parachute. A black-clad man jumping into the moonless night would be difficult to see, especially given the limited visibility, cloud cover and lack of ground lighting.^[57] The T-33 pilots did not make visual contact with the 727.^[58]

On December 6, 1971, 12 days after the incident, FBI Director J. Edgar Hoover approved the use of a U.S. Air Force SR-71 Blackbird to retrace and photograph Flight 305's flightpath,^[59] and attempt to locate the items Cooper carried during his jump.^[60]: 340 The SR-71 made five such flights; due to poor visibility, the photography attempts were unsuccessful.^[60]: 340 In an experimental recreation, flying the same aircraft used in the hijacking in the same flight configuration, FBI agents pushed a 200-pound (91 kg) sled out of the aft airstair and were able to reproduce the upward motion of the tail section and brief change in cabin pressure described by the flight crew at 8:13 pm.^[61][62] Initial extrapolations placed Cooper's landing zone within an area on the southernmost outreach of Mount St. Helens, a few miles southeast of Ariel, Washington, near Lake Merwin, an artificial lake formed by a dam on the Lewis River.^[63] Search efforts concentrated on Clark and Cowlitz counties, encompassing the terrain immediately south and north of the Lewis River in Southwest Washington.^[64][65] FBI agents and sheriff's deputies searched large areas of the largely forested terrain on foot and by helicopter. Door-to-door searches of local farmhouses were also performed. Other search parties ran patrol boats along Lake Merwin and Yale Lake, the reservoir immediately to its east.^[66] Neither Cooper nor any of the equipment he presumably carried were found.^[66]

Using fixed-wing aircraft and helicopters from the Oregon Army National Guard, the FBI coordinated an aerial search along the entire flight path known as Victor 23 in U.S. aviation terminology,^[67] and as "Vector 23" in most Cooper literature,^[48][68] from Seattle to Reno. Although numerous broken treetops and several pieces of plastic and other objects resembling parachute canopies were sighted and investigated, nothing relevant to the hijacking was found.^[69] Soon after the spring thaw in early 1972, teams of FBI agents aided by some 200 soldiers from Fort Lewis, along with Air Force personnel, National Guardsmen and civilian volunteers, conducted another thorough ground search of Clark and Cowlitz Counties for 18 days in March, and then another 18 days in April.^[70] Electronic Explorations Company, a marine-salvage firm, used a submarine to search the 200-foot (61 m) depths of Lake Merwin.^[71] Two local women stumbled upon a skeleton in an abandoned structure in Clark County; it was later identified as the remains of Barbara Ann Derry, a teenaged girl believed to have been abducted and murdered several weeks earlier by Warren Forrest, a suspected serial killer.^{[21]: 79 [72]} Ultimately, the extensive search and recovery operation uncovered no significant material evidence related to the hijacking.^[73]

Based on early computer projections produced for the FBI, Cooper's drop zone was first estimated to be between the Lewis River dam to the north and the town of Battle Ground, Washington, to the south.^[74] In March 1972, after a joint investigation with Northwest Orient Airlines and the Air Force, the FBI determined Cooper probably jumped over the city of La Center, Washington.^[75][76] In 2019, the FBI released a report detailing the burglary of a grocery store, about three hours after Cooper jumped, near Heisson, Washington. Heisson, an unincorporated community, was within the calculated drop zone Northwest Orient Airlines presented to the FBI.^[77] In the report, the FBI noted the burglar took only survival items, such as beef jerky and gloves; however, the report also noted the burglar wore "military type boots with a corregated [sic] sole", while Cooper was described as wearing slip-on shoes.^{[78]: 69 [78]: 124}

One month after the hijacking, the FBI distributed lists of the ransom serial numbers to financial institutions, casinos, racetracks, businesses with routine transactions involving large amounts of cash and to law-enforcement agencies around the world. Northwest Orient Airlines offered a reward of 15% of the recovered money, to a maximum of $25,000. In early 1972, U.S. Attorney General John N. Mitchell released the serial numbers to the general public.^[79] Two men used counterfeit $20 bills printed with Cooper serial numbers to swindle $30,000 from a Newsweek reporter named Karl Fleming in exchange for an interview with a man they falsely claimed was the hijacker.^[80][81]

In early 1973, with the ransom money still missing, The Oregon Journal republished the serial numbers and offered $1,000 (equivalent to $7,253 in 2025) to the first person to turn in a ransom bill to the newspaper or any FBI field office. In Seattle, the Post-Intelligencer made a similar offer with a $5,000 reward. The offers remained in effect until Thanksgiving 1974 although, despite several near matches reported, no genuine bills were found.^[82] In 1975, Northwest Orient Airlines's insurer, Global Indemnity Co., complied with an order from the Minnesota Supreme Court and paid the airline's $180,000 (equivalent to $1,100,000 in 2025) claim on the ransom money.^[83]

Analysis of the flight data indicated the first estimated location of Cooper's landing zone was inaccurate. Captain Scott—who was flying the aircraft manually because of Cooper's speed and altitude demands—determined the flight path was farther east than initially reported.^[84] Additional data provided by Continental Airlines pilot Tom Bohan—who was flying four minutes behind Flight 305—led the FBI to recalculate its estimates for Cooper's drop zone. Bohan observed the FBI's calculations for Cooper's drop zone were based on incorrectly recorded wind direction, and therefore the FBI's estimates were inaccurate.^[85]

Based on Bohan's data and subsequent recalculations of the flight path, the FBI determined Cooper's drop zone was probably over the Washougal River watershed.^[86] In 1986, FBI Agent Ralph Himmelsbach wrote, "I have to confess, if I were going to look for Cooper... I would head for the Washougal."^[87] The Washougal Valley and the surrounding areas were repeatedly searched but no discoveries traceable to the hijacking have been reported,^[84] and the FBI believes any remaining physical clues were probably destroyed in the 1980 eruption of Mount St. Helens.^[88]

On July 8, 2016, the FBI announced active investigation of the Cooper case was suspended, citing the need to deploy investigative resources and manpower on issues of greater and more urgent priority. Local field offices would continue to accept any legitimate physical evidence, related specifically to the parachutes or to the ransom money. The 66-volume case file compiled during the 45-year course of the investigation is preserved for historical purposes at FBI headquarters in Washington, D.C., and on the FBI website. All of the evidence is open to the public.^[89][90] The crime remains the only documented unsolved case of air piracy in commercial aviation history.^[91]

During their forensic search of the aircraft, FBI agents found four major pieces of evidence, each with a direct physical link to Cooper: a black clip-on tie, a mother-of-pearl tie clip, a hair from Cooper's headrest, and eight filter-tipped Raleigh cigarette butts from the armrest ashtray.^[25]

FBI agents found a black clip-on necktie in seat 18-E, where Cooper had been seated. Attached to the tie was a gold tie-clip with a circular mother-of-pearl setting in the center of the clip.^[7]: 124 The FBI determined the tie had been sold exclusively at JCPenney department stores but had been discontinued in 1968.^[92] By late 2007, the FBI had built a partial DNA profile from samples found on Cooper's tie in 2001;^[93] however, the FBI acknowledged no evidence linked Cooper to the source of the DNA sample. FBI Special Agent Fred Gutt said, "The tie had two small DNA samples, and one large sample ... it's difficult to draw firm conclusions from these samples."^[94] The FBI also made public a file of previously unreleased evidence, including Cooper's airline ticket,^[95] composite sketches and fact sheets, and posted a request for information about Cooper's identification.^[50][93][96]

In March 2009, a group of "citizen sleuths" using GPS, satellite imagery and other technologies unavailable in 1971^[97] began reinvestigating components of the case. Known as the Cooper Research Team (CRT),^[98] the group included paleontologist Tom Kaye from the Burke Museum of Natural History and Culture in Seattle, scientific illustrator Carol Abraczinskas, computer scientist Sean Christo and metallurgist Alan Stone. Although the CRT obtained little new information about the buried ransom money or Cooper's landing zone, they found, analyzed and identified hundreds of organic and metallic particles on Cooper's tie.

Using electron microscopy, the CRT identified Lycopodium spores, the source of which was likely pharmaceutical. The team also found minute particles of unalloyed titanium on the tie, along with particles of bismuth, antimony, cerium, strontium sulfide, aluminum and titanium-antimony alloys.^[98] The metal and rare-earth particles suggested Cooper may have worked for Boeing^[99][100] or another aeronautical engineering company, at a chemical manufacturing plant or at a metal fabrication and production facility.^[101]

The material with the most significance, explained Kaye, was the unalloyed titanium. During the 1970s, the use of pure titanium was extremely rare and specialized, and would only be used in aircraft fabrication facilities, or at chemical companies combining titanium and aluminum to store extremely corrosive substances.^[102] Cerium and strontium sulfide were used by Boeing's supersonic transport development project and by Portland factories in which cathode ray tubes were manufactured, such as Teledyne and Tektronix.^[103] Cooper researcher Eric Ulis has speculated the titanium-antimony alloys are linked to Rem-Cru Titanium Inc., a metals manufacturer and Boeing contractor.^[104]

FBI agents found two hair samples in Cooper's seat: a single strand of limb hair on the seat, and a single strand of brown Caucasian head hair on the headrest.^[105] The limb hair was destroyed after the FBI Crime Laboratory determined the sample lacked enough unique microscopic characteristics to be useful;^[28]: 233 however, the FBI Crime Laboratory determined the head hair was suitable for future comparison, and preserved the hair on a microscope slide.^[28]: 233 During their attempts to build Cooper's DNA profile in 2002, the FBI discovered the hair sample had been lost.^[106]: 62

In the armrest ashtray of seat 18-E, FBI agents found eight Raleigh filter-tipped cigarette butts. The butts were sent to the FBI Crime Laboratory,^[78]: 43 but investigators were unable to find fingerprints and returned the butts to the Las Vegas field office.^[28]: 228 In 1998, the FBI sought to extract DNA from the cigarette butts, but discovered the butts had been destroyed while in the custody of the Las Vegas field office.^[107]

On February 10, 1980, eight-year-old Brian Ingram was vacationing with his family on the Columbia River at a beachfront known as Tina (or Tena) Bar, about 9 miles (14 km) downstream from Vancouver, Washington, and 20 miles (32 km) southwest of Ariel. As he raked the sandy riverbank to build a campfire, he uncovered three packets of the ransom cash,^[108] totaling about $5,800.^[25] The bills had disintegrated from lengthy exposure to the elements, but were still bundled in rubber bands.^[109] FBI technicians confirmed the money was a portion of the ransom: two packets of one-hundred $20 bills each and a third packet of ninety, all arranged in the same order as when given to Cooper.^{[110]: 10–12 [111]}

The discovery caused new conjecture and ultimately raised more questions than it answered. Initial statements by investigators and scientific consultants were founded on the assumption the bundled bills washed freely into the Columbia River from one of its many connecting tributaries. A hydrologist from the U.S. Army Corps of Engineers observed the bills had disintegrated in a "rounded" fashion and were "matted together", indicating they "had been deposited by river action" as opposed to having been buried deliberately.^[112] The finding supported the hypothesis Cooper had landed near the Washougal River, which merges with the Columbia upstream from the discovery site,^[113] and not in or near Lake Merwin, the Lewis River or any of its tributaries feeding the Columbia River downstream from Tina Bar.