SEATTLE -- A man identified in a recent magazine article as possibly having been the infamous plane hijacker D.B. Cooper was almost certainly not him, the FBI said Friday.

While the man's face resembled a composite sketch of Cooper, the height, weight, eye color and skin tone were all too far off, said Special Agent Larry Carr, who has been assigned to the long-unsolved case for the past six months.

Cooper hijacked a Northwest Orient Airlines flight from Portland, Ore., in 1971, and parachuted out with $200,000 in ransom money. His fate remains unknown, but Carr said he believes Cooper died in the jump.

Lyle Christiansen, of Minnesota, believes his brother Kenneth, of Bonney Lake, Wash. - a Northwest employee and former paratrooper - was D.B. Cooper.

"I think he did it, there too many things that points to him," said Lyle Christansen.

Lyle, 77, said his brother was a trained Army paratrooper with the skills to survive a jump in harsh conditions.

But the man was 5-foot-8 and 150 pounds, at least 4 inches shorter and about 30 pounds lighter than Cooper. Kenneth Christiansen, who died of cancer in 1994, had hazel eyes, not brown, and he had pale skin, not olive.

"He's not a viable suspect," FBI spokeswoman Robbie Burroughs said.

Though the case has been dormant in recent years, Carr said he plans to reinvigorate it by releasing details never before seen by the public - including notes written by the flight attendants and conversations between the plane and the tower - in hopes that will prompt new clues.

In the hijacking, a man who identified himself as Dan Cooper boarded a plane headed for Seattle on Nov. 24, 1971, told the crew once the plane was in the air that he had a bomb and demanded $200,000 and parachutes.

When the plane landed at Seattle, he released the passengers in exchange for the money and ordered the pilot to fly toward Mexico. While in the air, Cooper apparently then jumped from the rear stairway of the plane.

The jumper later became known as D.B. Cooper after authorities questioned and then released a man named Daniel B. Cooper. That man was cleared but the name stuck.