A picture of his coffin leaving church appeared on the front of next day's New York Times. This was not because he was famous - although he was celebrated by peers in his profession of advertising and public relations - or a hero, although his service inVietnam earned him the American flag wrapped around his burial casket. Nor can an American citizen earn such coverage these days merely by dying, as Mosser did, in tragic and horrible circumstances: 15 people were killed in a plane crash that same week,and many were murdered each day, but their obsequies would never reach page one.
The reason the death of Thomas Mosser received such attention was that he had become the latest victim of one of the most elusive and clever criminals in modern American history.
At the requiem mass, the priest, Fr Neil O'Connell, asked, of Mosser: "Why should one of such personal and professional accomplishment be cut down at the moment of greatest fulfilment?" Then he said, of Mosser's killer: "Why should a mind capable of immense creativity and delicate precision become so perverted to produce such an instrument of fatal terror?"
The priest thought only God could answer these questions. After 16 years, the Federal Bureau of Investigation was probably beginning to agree.
At approximately 11am on Saturday 10 December, Mosser was standing in the kitchen of the large, airy, gabled frame house in North Caldwell he shared with his wife, Susan, and their four children, whose ages ranged from 21 years to 15 months. Nine days p r eviously, he had been promoted to the position of general manager at the advertising agency Young & Rubicam.
While his 13-year-old daughter, Kim, held a party elsewhere in the house, Mosser was opening the mail. A white package the size of a video-cassette, postmarked San Francisco, had arrived the day before, but he had only got round to it now. When he openedthe parcel, it exploded in his hands, blasting a hole in the kitchen counter and filling the room with smoke. Thomas Mosser was declared dead at the scene, reportedly decapitated.
Within a few hours, the FBI had concluded that the executive had become the newest victim in the 16-year bombing campaign of a criminal known only by the FBI case name of "Unabom", a coinage in which the "un" derives from "university" and the "a" from "airline", these institutions having been the first targeted by the terrorist. Mosser was the second person killed by Unabom - the North Caldwell device having been the most powerful dispatched so far - but 23 others had been wounded in 14 previous explosions.
The FBI investigation began in May 1978, after a security guard was injured by a bomb left on the campus of Northwestern University in Evanston, Illinois. A year later, another device exploded in the Technological Institute of the same university. In No v ember 1979, a bomb on an American Airlines flight resulted in smoke injuries to 12 people. The following June, the president of United Airlines was injured by a mail bomb sent to his Chicago home. Subsequently, at roughly annual intervals, explosions wou ld occur at academic or aviation centres.
In May 1985, the pattern widened both geographically and to include computers, the major target of the second phase of attacks, with a bomb left in the computer room of the University of California. In November of that year, Hugh Scrutton, the 38-year-old manager of a computer shop in Sacramento, California, was blown up when he opened a package. In February 1987, a shopper was injured by a bomb left on a parking lot behind a computer store in Salt Lake City, Utah. Then, for six years, nothing was heardfrom Unabom until two mail bombs injured a computer scientists and a geneticist at their homes in June 1993. The next victim - and second fatality - was Thomas Mosser.
The FBI - which, at times, has had as many as 45 agents working on the case - has no doubt that all 15 attacks are the work of the same person. Each of the devices has been shown on forensic examination to bear the initials "FC", which investigators believe to be what the New York Times coyly calls "an obscene phrase belittling computers".
It is assumed that Unabom wishes to fuck computers because of some Luddite grudge against technology. For the first 15 years, his victims were all in technical colleges, airlines or computer stores. The apparent extension of his range to include advertising executives is an unsettling new development, and the only connection so far found is that Mosser represented various blue chip technology clients, including Digital Equipment Corporation and Xerox, at Young & Rubicam, and Microsoft Corporation and Apple Computer in a previous 25-year career at the PR agency Burson-Marsteller. Mosser's promotion and CV may have been noted by the terrorist from business page coverage of his recent promotion.
Luddism is an unusual motive for a modern criminal. Although bombers figured in two Hollywood movies this year - Speed and Blown Away - the Dennis Hopper and Tommy Lee Williams characters were given careful anti-police and pro-IRA credentials. The profi l e of Unabom looks nothing like as neat and clear.
His trademark - apart from the obscene phrase belittling computers - is the manufacture of his bombs. They feature hand-carved wooden boxes, the switches are home-made and all the metal parts are sanded and polished. This cranky diligence, a refusal to use shop-made parts, may be either criminal cunning - preventing forensic detection of where he buys his materials - or another Luddite impulse: a rejection of machine-tooled parts.
After 16 years, there exist only three small clues to the identity of Unabom: a face and two names. The first is the result of a single sighting: a witness watched the positioning of the device behind the Salt Lake City computer store in February 1987. This description - of a white male in his thirties with a ruddy complexion, blond to red hair, and wearing shades and a hooded sweatshirt - was the basis for an FBI artist's drawing of the suspect.
The 1987 picture was waved again at the FBI press conference following the killing of Thomas Mosser. It is a measure of how little progress the investigation has made that - for a positive identification - they would have to rely on the bomber not havingchanged his appearance, or his sweatshirt, for seven years.
Apart from the speculative portrait, leads in the case amount to the mysterious names "Nathan R" and "HC Wickle". The first is from the imprint of a handwritten note found on the paper used in a letter apparently sent by Unabom - it bore the initials "FC" - to the New York Times last year, in which he promised "information" about his "goals" at a future date. On examination, the paper showed the shadow of a message: "Call Nathan R, Weds, 7pm." Appeals for Americans of this name to come forward have so far produced no clues.
"HC Wickle" was the return mailing name printed on the package that murdered Thomas Mosser. The addressee was identified as belonging to the Department of Economics at San Francisco State University. However, records show that no one with that name has studied or taught at that school. Last week, the FBI interviewed San Francisco residents with the surname Wickle, but no leads resulted.
And that is as close, after 16 years, as the FBI has got to Unabom. The nearest equivalent to the case occurred in New York in the Fifties, when a man called George Metesky planted home-made bombs at locations round the city. He injured 15 people before being caught. But the current invisible killer is proving both far more elusive and - as the family of Thomas Mosser can attest - far more lethal.
The FBI and the US Postal Service have established a confidential freephone number (1-800-BOMB) and posted a reward of $1m for information leading to the arrest of the bomber. By an irony - or deliberate goad - the investigators are also using computers to seek patterns in the mass of tiny clues and shrapnel evidence. This must make Unabom really mad, although it may also make him determined not to be caught that, or any other, way.
Meanwhile, the Mosser case suggests that his bombs are getting stronger, his grudge more general and - for the first time sending a mail bomb at Christmas, a time when post is supposed to be a particular delight - his mind more warped, as he contemplateshis 17th year of operations.