The DB Cooper Case Solved in 1200 Words

By Eric Ulis

In the next 1200 words I will solve the nearly 50 year-old DB Cooper case based upon facts available from the FBI and a man who has been a suspect in the NORJAK investigation from within one week of the skyjacking.

First let’s establish some facts per the FBI and the physical evidence.

  1. Cooper requested a flap setting of 15 degrees--a setting unique to the 727.
  2. Cooper knew where the oxygen bottles were stored on the 727.
  3. Cooper demonstrated familiarity with 727 refueling procedures and times.
  4. Cooper knew the 727’s rear airstairs could be deployed in-flight.
  5. Cooper’s clip-on tie contained commercially pure titanium, high grade Series 300 Stainless Steel and aluminum particles.
  6. Cooper’s clip-on tie was manufactured in 1963 or 1964.
  7. Cooper recognized Tacoma from the air.
  8. Cooper commented correctly that McChord Air Force Base was 20 minutes from SeaTac.
  9. Cooper’s ransom measured 11” X 12” X 6.5” which means it occupied a minimum of 858 cubic inches.
  10. Cooper’s ransom was delivered in an open-top, white canvas bank bag. This bag was 14” X 28” because the ransom would not fit into any of the three smaller versions.
  11. The bank bag, when stretched to its maximum volume, measured approximately 8.5” in diameter.
  12. The 14” X 28” bank bag allowed for a maximum volume of approximately 1360 cubic inches.
  13. The ransom, when delivered to Cooper, filled the bank bag to within at least 8” from the top.
  14. The bank bag when filled with the ransom provided for a maximum of 4” of material that could be utilized to cinch and close the top.
  15. Cooper had requested that the ransom be delivered in a knapsack and was displeased when it arrived in the open-top bank bag.
  16. Cooper complained that he would have to utilize one of the parachutes to secure the ransom because the money was not delivered in a knapsack.
  17. Cooper requested four parachutes (two mains and two reserves).
  18. Accidentally, one of the two reserves delivered to Cooper was inoperable because it was modified for use a demonstration parachute for ground use only. This reserve is known as the “dummy reserve.”
  19. The dummy reserve was missing when the skyjacked jet arrived in Reno.
  20. Flight Attendant Tina Mucklow witnessed Cooper using one of the reserves to store a portion of the ransom.
  21. Flight Attendant Tina Mucklow witnessed Cooper cutting shroud lines from the operable reserve which were then used to cinch the top of the bank bag and secure it to his person.
  22. The cannibalized operable reserve was left on the jet.
  23. Three rotting packets of Cooper’s ransom—approximately $5,800—was found buried in the sand with fragile rubber bands still intact along the Columbia River precisely 3,000 days after the skyjacking.

DB Cooper demonstrated knowledge of the 727 and possessed particles on his clip-on tie that strongly indicate that he was a former Boeing employee (Facts 1-5). Cooper also demonstrated familiarity with the Seattle region (Facts 7-8).

DB Cooper initially requested that Flight 305 depart Seattle with its rear airstairs deployed. The pilots rejected this request stating that the jet could not take off in this configuration. Cooper relented and allowed the jet to depart with the airstairs in the “up” position but demanded that Flight Attendant Tina Mucklow help him deploy the airstairs immediately upon take-off.

The airstairs request coupled with the fact that Cooper didn’t board with any luggage and that he couldn’t be certain he could occupy the last row of the flight from Portland—therefore may have had to abort the skyjacking—suggests that Cooper planned to originally jump in the Seattle area—probably the exurbs of Seattle.

However, there were two things that frustrated Cooper’s plan to jump near Seattle. First, the ransom arrived in the open-top bank bag which caused a delay as he crafted a solution to secure the ransom. Two, he had problems getting the airstairs to deploy once the jet departed Seattle, thus further delaying Cooper several additional minutes.

As noted above (Facts 9-14, 16, 20-21), Cooper had to remove multiple packets of the ransom from the bank bag to provide enough excess room to adequately cinch the top closed. These extra packets were then crammed into one of the reserves. Given that the dummy reserve was the missing reserve, it stands to reason that the dummy reserve was the one used by Cooper to secure the overflow packets of the ransom.

Fast forward to 1980: In February of that year three packets of Cooper’s ransom were found in a decayed state buried just below the surface on the shores of the Columbia River at a place called Tena Bar. Notably, rubber bands were still intact and immediately crumbled to the touch.

While the money find has been a mystery, it appears likely that Cooper buried the bag of money along with the excess packets of the ransom on the sandy beach shortly after parachuting from the jet. Additionally, it appears that Cooper later retrieved the ransom under cover of darkness, however, inadvertently left three of the excess packets behind. These were the packets discovered 8 years later after significant beach erosion at the spot where the money was found.

Now let’s discuss long-time FBI suspect Sheridan Peterson.

Sheridan Peterson first became a FBI suspect within one week of the skyjacking. Sheridan not only worked as a technical editor at Boeing from 1962 into 1964—note the tie’s manufacture date (Fact 6)he was also a former smokejumper in Montana for two years and was the founder of the Boeing Skydiving Club.

Furthermore, Sheridan was living in Nepal and did not work for 2½ years from September 1970 until March 1973. The skyjacking took place on November 24, 1971. Sheridan has been unable to provide an alibi for his time during the skyjacking.

Moreover, Sheridan was finally interviewed by the FBI twice in 2003. It was at this time that a sample of his DNA was collected and compared to a partial DNA profile lifted from Cooper’s clip-on tie. Sheridan is one of only three suspects to have had his DNA compared with the partial Cooper profile. The other two suspects were Duane Weber and LD Cooper. Notably, both Weber and LD have been publicly cleared by the FBI by virtue of their DNA comparisons. On the other hand, Sheridan has not been publicly cleared by virtue of his DNA comparison. In fact, the FBI continues to refuse to comment about the results of Sheridan’s DNA comparison.

Of utmost importance, in one of his 2003 interviews with the FBI, Sheridan explained that, “The shroud lines of the dummy reserve had been daisy chained so that the canopy could be shoved back into the pack easily.”

Consider the following carefully: Nothing has been publicly released that states how the dummy reserve was packed inside. Yet Sheridan, apparently not realizing this fact, proclaimed that the shroud lines were daisy chained—which would have been unusual. It would have been impossible for Sheridan to know how the dummy reserve was packed inside unless he actually looked inside. That fact puts Sheridan on the jet. That fact means that Sheridan was the person who opened the dummy reserve for the purpose of securing the excess packets of ransom. That fact proves that Sheridan Peterson was DB Cooper.