Soon the woman was receiving obscene phone calls and even visits to her house from strange men making lewd suggestions. According to Los Angeles prosecutors, the security guard had placed adverts on the internet in her name saying she was "into rape fantasy and gang-bang fantasy". The adverts included a detailed physical description, her address and phone number and even instructions on how to bypass her burglar alarm.
The case is the first instance of "cyber-stalking", or harassment by computer, to be prosecuted in California under a law introduced at the beginning of the year. The security guard was arrested a week ago, and already a second case is rearing its head: a 22-year-old Chinese American accused of sending anonymous hate e-mails to prominent Latino academics, business people and politicians in the Los Angeles area.
The law is helping to define a new category of crimes made possible by the development of computer technology and the internet: crimes in which the perpetrators believe they can hide behind the apparent anonymity of the PC screen in order to threaten, intimidate and spread hatred.
"This technology has created a whole new class of criminals who would not otherwise have the forbearance to terrorise people face to face. It emboldens them to hide behind computer screens and interfere with other people's lives," says Michael Gennaco, an assistant federal attorney specialising in the field.
And where there is a new category of crime, there are also novel methods for combating it. Instead of putting on the proverbial trenchcoat and going undercover, investigators are now spending more and more time in internet chat rooms responding to suspect adverts and engaging would-be molesters and child-abusers in one-on-one e-mail conversations.
"We managed to trap a police officer from San Diego who was attempting to solicit minors over the internet by having one of our investigators pose as a 13-year-old girl. Obviously that's a lot easier over the computer than it would be in real life, so in some ways computer crime has made our lives easier," recounts Scott Gordon, the district attorney who prosecuted the North Hollywood security guard.
In that case, the undercover operation was conducted by the victim's father, who responded to the advert in the hope of receiving messages from the perpetrator and so give specialised federal investigators the material they needed to track down their origin.
"It's like old-fashioned gumshoe work. We do our digging and ask a judge for a warrant, only in this case we're not searching a house or an office but asking an internet server to disclose customer information," says Mr Gordon.
Although the phenomenon is, by definition, a global one, California has taken the lead in combating it. The new law, which specifically refers to electronic communication as a possible medium for intimidation and harassment, grew out of the stalking and threat assessment division of the LA county district attorney's office, which in turn was the first of its kind when it was set up in 1991.
Curiously, it is not California's primacy in the computer field that has prompted such far-sightedness but rather the proliferation of Hollywood celebrities, who are not only frightened of stalkers but also have the media exposure and political clout to demand a response to the problem.
The stalking unit was set up in direct response to the murder in 1989 of Rebecca Shaeffer, a television actress. Al- though she fell victim to a man she had known well, not a deranged fan, the publicity was enough to force a political response. The OJ Simpson trial, which began as a stalking case, and the prosecution of a man making threats against Steven Spielberg and his family gave the unit greater prominence and clout.
Paradoxically, celebrity stalking accounts for a tiny percentage of the team's overall caseload - 90 per cent is caused by domestic friction between present or former partners.
But the celebrity world has a strange effect on public policy, and vice versa: when a former boyfriend was caught stalking the actress Andrea Thompson a couple of years ago, it not only gave the DA's office a case it could successfully prosecute but also transformed the part Ms Thompson played on the television series NYPD Blue from an insignificant background character to one of the show's protagonists.
Mr Gordon and his team are reluctant to discuss the means stalkers and other criminals use to conceal their identities over the internet, but it seems many people are remarkably naive about how anonymous they can be. Special FBI computer forensics teams can locate the origin of just about anything, but most of the time such fancy technology is not even needed.
"Almost all stalking cases, not just on the internet, get solved pretty quickly," says the DA. "People assume computers have some kind of veil of mystery, but they are wrong."Reuse content