Seeking the "real" DB Cooper

By Eric Ulis

On Thanksgiving Eve 1971, a man calling himself Dan Cooper skyjacked a Northwest Orient flight travelling from Portland to Seattle. Upon landing in Seattle, Cooper ransomed the passengers for $200,000 and four parachutes. He then directed the jet to take-off and head to Mexico City by way of Reno for a fuel stop. Approximately 36 minutes after departing Seattle, somewhere just north of Portland, Cooper parachuted out of the back of the jet never to be seen or heard again.

Who D.B. Cooper was and whether he lived or died is still a mystery today. In fact, this is the only unsolved skyjacking in United States history. Furthermore, in 2016 the FBI finally gave up the investigation into the D.B. Cooper case by administratively closing the case after nearly 45 years.

As an aviation buff, the mystery surrounding D.B. Cooper drew me in as a kid in the late 70s. It was one of those real-life mysteries that for me was simply too intriguing to ignore. On the other hand, as I’ve followed the Cooper mystery over the years, it’s been frustrating to see false information and suspects put forward as the D.B. Cooper cottage industry has flourished. I’m one of those people who lack patience when it comes to grand conspiracy theories and the like. I prefer truth over fantasy.

With this in mind, ten years ago I decided to undertake a serious, no-nonsense, fact-based investigation of my own into the D.B. Cooper mystery. My hope was that I would be able to determine whether Cooper had survived, and perhaps who the man actually was. It was a tall order, but with the advent of the Internet, the passage of time, and the release of heretofore secret information regarding the case by the FBI, I decided to give it a shot.

From the beginning I decided the best way to investigate the case was to follow a four-point blueprint. First, I would investigate the event and attempt to ascertain the facts. Second, I would investigate additional evidence that had been discovered in later years with advances in technology. Third, I would create a suspect profile.

Finally, I would investigate newly released FBI files in an attempt to identify a suspect based upon my belief that the real D.B. Cooper was probably already a suspect, however, one that the authorities could not implicate “beyond a reasonable doubt.” After all, we have all heard of cold cases that eventually get solved due to enhances in DNA testing and the like, only to learn that the guilty party had, in fact, been on law enforcement’s radar for some time.

The backbone of my investigation centered on several thousand pages of heavily redacted FBI files that had recently been obtained through the Freedom of Information Act (FOIA). While often dry, the files were quite entertaining at times—especially in the area of investigating suspects. I recall one guy who contacted the FBI stating that he was watching the Perry Mason television show and noticed that one of the supporting actors bore a strong resemblance to the FBI’s D.B. Cooper sketch. Another guy contacted the FBI stating that he had been at a bar and noticed the man next to him with a lot of cash in his wallet as he was paying his bar tab. Then there was the guy who claimed to have created a divining device that would help locate the money—the device was a contraption utilizing some wires in a jar of water and, of course, Alka-Seltzer.

Joking aside, the FBI files did contain a lot of valuable information. Ultimately these files piqued my interest in a suspect who had come to the FBI’s attention within a week of the skyjacking. While I did not know the suspect’s name, I did know identifying information about the man. Specifically, that he had graduated from Santa Rosa Junior College in 1949 and later from the University of Missouri in 1954. I also knew that he had been a Montana smokejumper beginning in the early 1950s as a summer job while at Mizzou. Furthermore, I learned that he later worked for Boeing in Seattle and had obtained a DOD clearance while at Boeing providing him access to secret information in their Aero-Space Division.

All of this was very important because I knew that D.B. Cooper had displayed detailed knowledge of the Boeing 727 airliner that could have only been obtained by someone with a measure of access to secret 727 data. Additionally, later analysis of a clip-on tie that D.B. Cooper left behind on the jet, apparently by mistake, determined that the tie contained pure titanium particles, aluminum particles, microscopic steel shavings and some traces of rare earth elements. The titanium, in particular, was noteworthy because titanium was rare back in 1971 and appeared to indicate that Cooper was a former employee of Boeing which was a place where all of these particles could be found.

I decided to contact both Santa Rosa Junior College and Mizzou to obtain public information about their graduates in an attempt to determine the name of the suspect referred to in the redacted FBI files. I surmised that if I found the same name on both the graduating lists from SRJC in 1949 and Mizzou in 1954 that this would be my guy. As it was, there was one name common to both lists, Sheridan Peterson.

Once I had the name of my primary suspect I quickly learned a lot about Peterson, not the least of which was that he was (and is) still alive at 92 years of age. Furthermore, it provided me the opportunity to reach out to Sheridan and speak with him directly.

To date I have talked with, texted and emailed Sheridan dozens of times. This communication taught me a lot about the man and ultimately led me to identify Sheridan Peterson as D.B. Cooper.

Among the more compelling items that I learned about Sheridan during my investigation are the following:

  • He is one of only three people known to have had their DNA compared with a partial DNA profile extracted from Cooper’s tie—this among a field of approximately 1500 suspects. The other two are Duane Weber and Lynn Doyle Cooper.
  • He is the only one of the three DNA-compared suspects that the FBI has not publicly cleared by virtue of his DNA.
  • He was formerly employed by Boeing as a technical editor with access to the commercial and aerospace divisions as well as the Super Sonic Transport (SST) project.
  • He was an experienced skydiver with smoke jumping experience and described as a maverick and fearless in skydiving circles.
  • He was living in Nepal during the 1971 skyjacking, not employed at the time (2 ½ years), and provided an alibi that has since been disproved.
  • He opened a confidential numbered bank account in 1971.
  • D.B. Cooper’s tie clip was sold as a set that also included a tie tack, cufflinks and money clip. Sheridan owned a pair of the cufflinks that were included in these sets.
  • In a 2003 interview with the FBI, Sheridan described the “dummy reserve” (missing parachute) in terms only the skyjacker could have known.
  • He has refused to directly confirm or deny being D.B. Cooper when specifically asked by the FBI.
  • He resembled the physical description given by witnesses.

Of particular interest has been my communication with the FBI concerning Sheridan. I have attempted on multiple occasions to get the FBI to either clear him as a suspect—as has been done concerning other suspects—or clarify their position regarding Sheridan. Thus far, all my efforts have been rebuffed which tells a story in and of itself.

More to the point, I ultimately concluded that the FBI strongly suspects that Sheridan is Cooper. However, because of significant problems with their case—including the loss of critical pieces of evidence, specifically, eight Cooper cigarette butts—they, along with the Assistant United States Attorney in Seattle, decided that the strength of their case did not meet the appropriate legal threshold. Therefore, the case was administratively closed in 2016.

That said, the FBI has left the door open if new evidence, specifically the ransom money or parachuting rig, is discovered. However, after nearly 50 years, in all likelihood the case will forever go officially unsolved.

Nonetheless, I believe there is still one man out there who knows the truth of it all who can actually put the matter to rest in its entirety. But time is running out. Sheridan Peterson is 92 years old and in poor health.

To be clear, Sheridan has never admitted to anyone, that I am aware of, that he was D.B. Cooper. But, knowing him as I do, it is clear to me that there is a lot he is concealing. I have even gone as far as reaching out to the United States Attorney’s office in Seattle to discuss the prospect of a no-jail-time plea if I could obtain the necessary information and evidence to close the case. However, my request went unanswered.

My ten year investigation into the D.B. Cooper case culminated in the release of a 135-page report titled DB Cooper: The Definitive Investigation of Sheridan Peterson on July 3, 2018.