Devout 'Clive Swenson' attended 7am mass in Jersey City most days before going to work as a carpenter on a building site. Fellow workers noted his religious fervour and flashes of a keen intelligence.
Four hundred miles away in a Buffalo suburb Dr Barnett Slepian, an obstetrician who performed abortions, was shot dead in his kitchen as he chatted to his wife and one of his four children. The fatal bullet, from a high-powered rifle, was fired through a window late at night.
After the killing in October 1998, the man called Swenson vanished from Jersey City, leaving little more than some fast-food cartons and an undertaker's calendar.
Over the next two and a half years the FBI followed his trail, via Newark airport, a computer link in Brooklyn, across Ireland and to Brittany where the alleged killer - real name, James Kopp - was arrested last week.
Kopp was well-known in militant anti-abortion circles, where he was nicknamed Atomic Dog. Drawn to the cause after a girlfriend had a termination, he used his practical skills in the Seventies and Eighties to design intricate locks that protesters fastened to abortion clinic doors.
This weekend he is being held in the Breton city of Rennes, refusing to answer interrogators' questions. He had been run to ground after an extraordinary operation by police and the FBI.
His connection with the militants would have made him a suspect even if a jogger had not noticed his Chevrolet near the murdered doctor's home in the suburb, Amherst.
The car, later found at the airport, contained a hair that closely matched Kopp's. FBI agents discovered a Russian-made sniper's rifle buried behind the doctor's house.
The trail led to America's shadowy, loose-knit group of violent anti-abortion activists and, in particular, to a Brooklyn couple, a convicted abortion clinic bomber called Dennis Malvasi and his wife Loretta Marra. They were also arrested last Thursday and charged with conspiracy to aid, fund and shelter Kopp.
Several weeks ago, the FBI learnt Kopp was in Ireland, living cheaply under false identities. He had been there at least since March last year, doing a series of menial jobs.
He worked for a week as a temporary typist at the City of Dublin Skin and Cancer Hospital, adorning his desk with religious statuettes. He had shaved off the goatee beard pictured on a poster putting him on the FBI's 'Ten Most Wanted' list.
Irish pro-life groups yesterday denied they had harboured him. But an FBI spokesman said: 'He did not leave the US without assistance, and he did not remain a fugitive without assistance.'
Kopp fled Ireland one step ahead of the police on a ferry to Britanny on 12 March. He had two Irish passports as well as his own US document.
Last Thursday French police descended on a post office in the medieval Breton town of Dinan to arrest a gaunt, hollow-eyed man in a frayed sports shirt. He had just picked up a package from New York that contained $300. The man - anxious, broke and ill - was Kopp.
Kopp has known Loretta Marra at least since 1990, when they were arrested at an anti-abortion protest in Vermont and jailed for two months. In 1991 they shackled themselves outside an abortion clinic in Levittown, New York. The emergency services wheeled them away on a cart to be cut free in a workshop.
Kopp is a suspect in three non-fatal ambushes of doctors in Canada and another in Rochester, New York state.
Just four months after the murder of Slepian in 1998, the bomber Malvasi told a grand jury he did not know Kopp, but refused to say if he knew Marra.
The FBI began to track Kopp through Malvasi and Marra. Agents secured secret court warrants allowing them to record their telephone conversations, snatch computer data, drop listening devices into their apartment and sneak into photograph incriminating letters, according to court documents.
The ingenious Kopp was using email sent through an account with the internet service provider Yahoo! Text was deposited in draft folders so the sender could not be traced. Replies could be sent with similar anonymity.
A code was used, which the FBI cracked. The word 'margin' meant 'border', 'jackie' was entry route and 'diagnosis' signified detection by the authorities.
In France last week the bureau tapped his calls from phone boxes. It was a monitored call that told agents when Kopp would visit the post office at Dinan to with draw money from Brooklyn so he could start travelling again.
'The sooner I get about 1,000, the sooner you see this smiling cherubic face,' the fugitive allegedly wrote to Marra on 21 March in an anonymous email.
'I know of no problems,' Marra is said to have replied. 'We are convinced the mere fact of you being undiagnosed enough to stand around on the street and make phone calls is complete proof that you are not diagnosed at all. Can't wait to see you.'
Marra and Malvasi had told Kopp 'the coast is clear' for him to return to the US via Canada, making his way to New York by train or bus. He was to use their home as a safe house, it is alleged. The couple would change their names to Ted Barnes and Joyce Maier.
The US authorities now face a battle to have Kopp extradited. He is wanted for second degree murder in New York state, for which the maximum penalty is life. He could, however, be executed on a complex federal murder charge, formally described as using a firearm to prevent Sepian performing his professional duties.
But the French authorities will refuse the extradition unless there is a guarantee that he will not be sentenced to death. This is a requirement of French law to which, said a Ministry of Justice spokesman, no exceptions had yet been made.
Even if the US authorities can resolve the problem over a possible death penalty, it could take up to 18 months for Kopp to be sent back to stand trial in the US.
The case is seen in Washington as a test of the rigour of the new Attorney-General John Ashcroft, who has publicly expressed his own fervent opposition to all kinds of abortion many times. He thinks it should be made illegal even for pregnancies resulting from rape and incest.
Ashcroft said last week: 'We are committed to bringing Mr Kopp back to face these charges.'
Earlier in the week a federal appeals court in San Francisco upheld the right of anti-abortionists to publish on the internet the so-called Nuremberg Files, a virtual hit list of doctors who carry out abortions.
Within hours of Slepian being shot dead, his name had been posted on the files with a cross through it.
