Sheridan Peterson, who passed away on 8 January according to memorial website Legacy.com, was thought to possibly be the “Dan Cooper” who hijacked Northwest Orient Flight 305 on Thanksgiving eve 1971.
Mr Cooper handed a flight attendant a note saying that he had a bomb and then demanded $200,000 in $20 bills and four parachutes.
When the flight landed in Seattle, the hijacker exchanged the flight’s 36 passengers for the money and parachutes and ordered the flight crew to take off and head for Mexico City.
Somewhere between Seattle and Reno, Nevada, Mr Cooper jumped from the rear door of the aircraft with a parachute and the ransom money.
The pilots landed the plane safely, but the identity of the hijacker and what happened next remains a mystery to this day.
Mr Peterson was considered a chief suspect due to his experience as a smokejumper — a firefighter that parachutes into remote areas to tackle wildfires — and love of skydiving. He served as a marine during the Second World War and later worked as a technical editor at Seattle-based Boeing.
Indeed he wrote about possibly being DB Cooper in an article for the National Smokejumper Association’s magazine.
“Actually, the FBI had good reason to suspect me,” he wrote. “Friends and associates agreed that I was without a doubt DB Cooper. There were too many circumstances involved for it to be a coincidence.”
“At the time of the heist, I was 44 years old. That was the approximate age Cooper was assumed to have been, and I closely resembled sketches of the hijacker.”
On another occasion a photo came to light from a Boeing newsletter showing him dressed in exactly the same manner as the hijacker was said to have been during the 1971 flight.
Mr Peterson insisted that he was in Nepal at the time of the hijacking, but nevertheless was still considered a prime suspect by the FBI.
Eric Ullis, an entrepreneur from Phoenix, spent years trying to establish the real identity of DB Cooper. He concluded that he was “98 per cent” certain that Mr Peterson had carried out the daring heist.
DNA collected from a tie Mr Cooper was wearing on the plane has been tested, but no match was found.
Mr Peterson is by no means the only person identified as DB Cooper. An HBO documentary released in 2020 called The Mystery of DB Cooper profiled several contenders.
Another theory is that Mr Cooper did not survive when he jumped from the aircraft as he would not have been able to steer his parachute and was over a wooded area in unsuitable clothing and footwear.
In 1980, a young boy found a rotting package of $20 bills totalling $5,800 with serial numbers that matched those of the ransom money lending credence to the theory.