CHICAGO -- It is considered one of the great unsolved mysteries of FBI history: how a seemingly quiet man in his mid-40s hijacked an airliner somewhere between Seattle and Reno, Nev., in November 1971, then parachuted out in his loafers and trench coat, making off with $200,000 in cash.
Who was he? Did he survive?
After all these years, federal authorities say they still do not know, and the case lingers and vexes and fascinates as the only unsolved airplane hijacking in U.S. history.
"It's a mystery, frankly," FBI officials said in a December news release issued periodically to update old cases.
But now, with the advantage of technologies that were not available decades ago and with newfound attention from an agent on the West Coast, the FBI has announced that the cold case is officially hot again - and the search is on for the hijacker who called himself Dan, and sometimes, D.B. Cooper.
And, for the first time, the FBI is providing pictures and information on the Cooper case to the public on its Web site, www.fbi.gov.
The agency hopes that pictures like the one of Cooper's black tie, which he removed before jumping, will prompt a memory, or that someone will offer fresh insight into what happened to all that cash, some of which was scattered in the wilderness and found by a young boy in 1980. (Already, a DNA sample taken from the tie has ruled out several men who claimed to be the parachuting hijacker.)
"This case is 36 years old, it's beyond its expiration date, but I asked for the case because I was intrigued with it," said Larry Carr, a federal agent based in Seattle who usually investigates bank robberies. He was 4 when the hijacking occurred.
"I remember as a child reading about it and wondering what had happened. It's surreal that after 36 years here I am, the only investigator left. I wanted to take a shot at solving it."
Since the case was turned over to him about six months ago, Carr has come up with a new way of seeing the incident: as a bank robbery that just happened to be on an airplane. The fresh perspective led to new investigating techniques.
"The classic way we solve bank robberies is with the public," Carr said. "Everything we know - pictures, descriptions, M.O., everything - we put it all out there."
Now, with the information made public, he said, "maybe someone will say: My uncle who disappeared in 1971 - he could have been Cooper. I just never thought about it until now."
Included in the newly released information are several updated insights on Cooper that the FBI feels are accurate: He was not an expert skydiver, he had no help on the ground, he was about 6 feet tall and 175 pounds, with brown eyes.
The physical description came from separate accounts given by attendants on the hijacked flight, Northwest Airlines 305, that left Portland, Ore., bound for Seattle on Nov. 24, 1971.
After takeoff, Cooper handed a flight attendant a note saying he had a bomb in his suitcase. He demanded four parachutes and $200,000 in $20 bills, the FBI says.
Upon the plane's landing in Seattle, Cooper exchanged all 36 passengers for the ransom, but he continued to hold several crew members on the plane with him as, on his orders, it took off again, this time on a flight to Mexico City.
Around 8 that night, Cooper jumped out of the back of the plane as it was flying somewhere between Seattle and Reno. It later landed safely.
The FBI opened an investigation while the airplane was still in flight, but despite years of work and the consideration of hundreds of suspects, Cooper seems to have disappeared into the night.
"If he's alive today, he'd be about 85 years old," Carr said. "Maybe one day I'll be sitting at my desk and I'll get a call from an old man who says, 'You're not going to believe this story.'"