PORTLAND, Ore. (KOIN) – It happened 51 years ago Thursday. A man the world knows as D.B. Cooper walked into the Portland International Airport the day before Thanksgiving, paid $20 for a one-way ticket to Seattle and became the most infamous skyjacker in U.S. history. 

The case has never been solved. 

In 1971, Dan Cooper (who became known as D.B. Cooper) hijacked that jet bound for Seattle and when it landed, Cooper exchanged the passengers for $200,000 and four parachutes. 

Cooper demanded to be flown to Mexico. While flying in the escape plane over Southwest Washington, he parachuted out, vanishing into thin air with the money. 

He was never seen again. 

However, two weeks ago, an amateur D.B. Cooper investigator revealed new leads in the case

Eric Ulis shared a picture of Vince Peterson who died in 2002. Ulis said he traced a rare form of titanium found on the black tie that D.B. Cooper left on the Boeing 727 to a laboratory where Peterson worked near Pittsburgh, Penn.