Detective McLaughlin's job is standard police work, with one exception: He hunts paedophiles via the Internet. And he's good at it. Fewer than 50 law enforcement officers in the United States track paedophiles full-time by computer. McLaughlin may soon join them. But even as a part-time cybersleuth, his doggedness has led to 75 arrests since 1996, some of visitors from as far away as Norway who stroll the Internet trading child pornography or looking for sex with children.

His day begins with deception. Within seconds of logging on to an Internet chat forum and posing as a teenage boy, McLaughlin, 41, is hit on. ``Want to trade?'' the man writes, hoping to swap pictures of naked children. I am brand new,'' McLaughlin responds. Can you send a few?'' the cop won't transmit child pornography, he lets others make the first move. If you have self pics,'' comes the response.

McLaughlin sends a porn-free picture, supposedly of himself. You like guys my age?'' Yes... .''

A picture of a naked boy appears on McLaughlin's screen at the police station in Keene, a town in this pastoral northeastern state. The caption says he is twelve years old.

It is followed by a second photo of another naked boy, this one posing suggestively while pulling a shirt over his head.

A third image appears, of a fully-clothed man in his 30s. Supposedly the sender.

``It's probably really him,'' McLaughlin says. They're that stupid.''Stupid or not, they know he's out there. McLaughlin has a global reputation for taking down paedophiles. While posing as a teenager during an Internet chat with a suspected paedophile in Norway, McLaughlin got an eyeful.Watch out for this guy. He's out to get guys like us,'' the man warned, sending a digitised image of the detective taken from an article about his Internet sleuthing.

Philip Rankin, a citizen of Britain living in Norway, learned that the hard way. He and a Keene boy exchanged e-mail for months, and the two arranged to meet for sex in March.

But when Rankin arrived in Keene, the attractive boy turned out to be a middle-age man with a badge and a gun. Rankin is charged with attempted felonious sexual assault. If convicted, he faces up to seven years in jail, then deportation.

That is the power of the Internet, McLaughlin says. It allows police in a city of only 23,000 residents to make a difference in global crime. ``It's discouraging who we're finding,'' he says. But I wonder if we ever would have found them without this technology.''

That technology also offers a good hunting ground for paedophiles who use the anonymity of the Internet to woo children, elicit their trust and ultimately arrange a meeting.

That anonymity often bolsters a bravado but hastens a downfall. Many paedophiles brag in chat groups about sexual conquests, even trading pictures of victims. That information can later be used against them, McLaughlin says.

McLaughlin joined the police force in 1981 and specialized in sex offenders. He began focusing on Internet crimes about 18 months ago, when a Keene couple claimed that a woman was using e-mail to seduce their teenage son.

That's also when McLaughlin became aware of an article published by the North American man/boy love association, an organisation based in New York that advocates sex between men and boys, that gave instructions for using the Internet to find young partners.

Ten per cent of McLaughlin's arrests involve suspects with prior convictions for molestation or child pornography. Fifty per cent had ready access to children.

Fewer than five per cent of child molesters are caught, he says due mostly to a shortage of law-enforcement personnel. By the time molesters are caught, most have assaulted an average of 150 to 200 children. McLaughlin now hunts part-time, but that could change in September. The department has applied for grants to set him up full-time.