In a 30-minute news conference held here today, Christopher G. Bubb, a New Jersey deputy attorney general, said AOL's information led authorities to a telephone number, then to the place where the Word macro virus was posted to the Internet. Finally, it took them to David L. Smith, the 30-year-old network programmer who was arrested Thursday night at his brother's house in nearby Eatontown, New Jersey. "With that [AOL] information we were in a position to identify the specific place where access was gained to the Internet," Bubb explained. "Through that we were able to track it back to a specific telephone that was used." AOL representative Kim McCreely said AOL discovered the lead "through an internal investigation, looking into the virus, and seeing what it had infected." Bubb and the other officials representing the inter-agency team that cooperated in cracking the case also said a controversial Microsoft document identification technology did not play a significant role in leading to the arrest -- as had been widely speculated. The technology assigns a unique serial number to files produced by Word, Excel and other applications included in Microsoft Office 97 and Office 2000. William Megarry, an FBI special agent, said authorities have yet to pinpoint a motive. "Who can get into the mind of a guy like this?" Megarry said. "Whether he meant more harm or just mischief -- who knows?" "This affected hundreds of thousands of computers in workplaces," Megarry said. "We'll leave it up to the jury to decide how serious this is." Smith, of Aberdeen, N.J., was released on $100,000 bail Friday morning. He will be arraigned on Monday. He faces several charges, including interruption of public communications, conspiracy to commit the offence, attempt to commit the offence and third-degree theft of computer service. All together, the charges carry a maximum penalty of 40 years in prison and a $480,000 fine. It was unclear whether the conspiracy charge meant other people were involved. Under New Jersey law, only one person needs to be involved to face conspiracy charges. Smith may also face more charges under federal law, New Jersey officials said. Smith was snared with the help of America Online technicians, and a computer task force composed of federal and state agents. Agent Megarry cited the joint effort as proof of how serious law enforcement authorities consider viruses, characterising them as electronic sabotage. According to authorities, Smith originated the virus from his apartment in Aberdeen. They said the virus is named after a topless dancer from Florida, where Smith used to live. Gumshoe police work State Attorney General Peter Verniero, who appeared at the press conference along with New Jersey Gov. Christie Whitman, said authorities found Smith through "good old-fashioned gumshoe police work,'' canvassing neighbourhoods and identifying other family members who led them to Smith's brother's house. Verniero would not release the brother's name. Smith cooperated with authorities when they arrived to arrest him, Verniero said. The Melissa virus appeared last Friday and spread rapidly around the world on Monday like a malicious chain letter, causing affected computers to fire off dozens of infected messages to friends and colleagues and swamping e-mail systems. Earlier last week, experts had said there were clues that the virus writer had distributed the virus using an account stolen from America Online 15 months ago. Take me to the Melissa virus special.