The author of the AnnaKournikova virus has been arrested by the Dutch authorities, only hours after posting an apology for creating the virus on the internet.

Antivirus experts said that the news should be taken as a warning that authorities are cracking down harder on malicious code writers.

The author, reportedly a 20 year-old from Friesland in The Netherlands, was detained by Dutch police on suspicion of damaging computer programs and property.

The police had initially been investigating internet postings from a user calling himself OnTheFly, which is the name of the virus writer as located in the virus source code, tracing his connection back to the Excite@Home network. The service provider then came up with a name and address to help the police track their suspect.

The newsgroup user claiming to be OnTheFly posted messages which admitted to writing the virus and said: "I never wanted to harm the people [who] open the attachment. But after all, it's their own fault they got infected."

Graham Cluley, senior technology consultant at Sophos, welcomed the news. "People forget the power of newsgroups. It would have been fairly easy to trace whoever posted those admissions to writing the virus," he said, adding that it was good to see the authorities move in so quickly and that he "was not surprised to see an arrest so soon".

Cluley warned that the suspect could get as much as four years in prison if found guilty. "It is the virus writer's fault after all, no matter what he may say otherwise," he said.