With a Family Discovery, a Manhunt Comes to an End

Year after year and death after death, investigators looked everywhere, from the checkout records for certain library books to the computer files of known criminals, from the storefronts of scrap metal dealers to the employee lists of companies dealing in artificial human limbs.

They took each clue they came across -- no matter how small, no matter how dubious -- and wrung as many leads out of it as they could. They picked the minds of experts in fields running the gamut from handwriting to forensic psychiatry.

At one point, appealing to the public, they set up a toll-free telephone number with a chilling suffix: 1-800-701-BOMB. At another, appealing to the unknown, they actually consulted a clairvoyant.

By the time the search apparently came to an end yesterday, 18 years after it began, with the capture of a man believed to be the Unabomber in a remote shack in the Montana wilderness, it had become one of the most extensive, intricate and endlessly frustrating manhunts in the history of the Federal Bureau of Investigation.

"What a relief this is for them," said Michael Rustigan, a professor of criminology at San Francisco State University who has studied the case for the last 15 years. "They have spent more money and more energy on solving this Unabomber case than almost all other serial killer cases put together."

Their efforts combined old-fashioned detective work with newfangled technology, and drew on both the formidable financial reserves of the Federal Government and the considerable acumen of some of the best criminologists in the business.

Literally thousands of people were interviewed, and three different federal agencies -- the F.B.I., the Bureau of Alcohol, Tobacco and Firearms and the Postal Inspection Service -- were involved in the pursuit.

Investigators moved from Washington to Salt Lake City, from San Francisco to Chicago, as they targeted a killer who left a string of hints, sometimes on purpose, that were as cryptic and tantalizing as those imagined by the writers of popular crime fiction.

Every few years, it seemed, there was a fresh tidbit, small but promising. And every few years, there was a fresh stab of frustation, as a man pursued by legions of the smartest, most experienced investigators in the country somehow managed to remain as mysterious and elusive as an apparition.

"You keep chewing on the same thing, hoping to go further, but it's just not there," John C. Killorin, a spokesman for the Bureau of Alcohol, Tobacco and Firearms, said in 1993. "Ultimately, you reach the point where there is no more work to be done."

So investigators would wait, and hope, and worry.

Some of their best leads came only last year, from the long manifesto by the Unabomber that was published in The Washington Post on Sept. 19.

And the publication of the manifesto was apparently a crucial part of yesterday's breakthrough, enabling family members of the man believed to be the Unabomber to grasp the significance of some old writings of his that they came across, according to law enforcement officials.

These writings seemed strikingly similar to the Unabomber's other communications, and through an intermediary the family contacted the F.B.I.

From the beginning, in 1978, the Unabomber made investigators' jobs difficult. He fashioned his own bombs, usually using such common materials as scrap wood and lamp cord, so that nothing about the devices was able to be traced.

But as if to taunt those trying to track him, he often left a signature on the devices that survived the explosions -- the initials FC, which was eventually understood to stand for Freedom Club.

For most of the first decade of the manhunt, the three federal agencies operated separately, a situation that some critics believe hampered their efforts. One of the first big potential breaks came in 1987, when a witness spotted a man believed to be the Unabomber.

The witness saw the man deliver a package that later exploded, maiming someone, in the parking lot of a computer sales company in Salt Lake City. The description that the witness provided yielded the crude, widely circulated sketch of the Unabomber as a mustachioed man in sunglasses and a hood.

This lead, like so many others, did not take investigators far, but some of them believed it was the reason that the Unabomber ceased his campaign of terror for the next six years, not striking again until 1993.

The investigators pressed on. In 1991, using the profiling techniques becoming widespread in the tracking of serial killers, investigators developed a psychological portrait of the Unabomber as an obsessive-compulsive white man who had probably held a string of menial jobs.

He would be a neat dresser, a meticulous keeper of lists and a polite neighbor who kept his demons buried deep inside, investigators speculated.

After the Unabomber struck twice in June 1993 and also mailed a letter to The New York Times, investigators had a new set of clues. Because these missives had featured postmarks from Sacramento, Calif., the FBI set up a new operation in San Francisco, moving about 45 agents into northern California and plumbing the possibility that the Unabomber was on the West Coast.

By carefully analyzing a piece of paper in one Unabomber's communication, investigators detected traces of a piece of writing otherwise invisible to the human eye.

It spelled out a message of uncertain significance -- "Call Nathan R wed 7 pm" -- that sent investigators on another elaborate computer and paper chase as they literally set out to contact roughly 10,000 Nathan R's nationwide.

Investigators also determined that some of the materials used in packaging his bombs were similar to materials used for artificial human limbs, and wondered if the Unabomber had worked for such a firm.

All the while, investigators updated banks of computer information on the Unabomber, cross-referencing it with other computer databases.

Toward the end of 1993, in gestures that bespoke their waxing frustration, investigators announced the toll-free number and offered a $1 million reward for information leading to apprehension of the Unabomber.

The search grew more urgent as the Unabomber's makeshift explosives became more powerful. Investigators scoured the attendance rolls of universities they believed the Unabomber might have attended; at one point, they even interviewed college art teachers, operating on the presumption that the bomber might have learned his metal fabrication skills in a class.

Investigators increasingly concentrated their efforts in the Northwest, where they believed the Unabomber was living, and especially in northern California, where they believed he might have radical associates who shared his expressed wish to destroy the industrial system.

In 1995, investigators canvassed scrap metal dealers in California, trying to find someone who might have sold the Unabomber materials used in his bombs.

They also paid visits to leftists and environmental radicals living in the San Francisco Bay area, particularly in Berkeley, literally showing up on people's doorsteps. In some instances, they were looking for leads. In others, they were actually hoping to come face to face with the Unabomber himself.

One person they interviewed at the time, Garth Smith, said in August, "If they were looking for someone like me, they must not have a clue about who this guy is."

In another few months, at long last, they would.