A 45-year-old Cyprus man has been arrested for allegedly using a Trojan horse to control a teenage girl's computer and use her own webcam to spy on her in her bedroom.

According to police reports, the man, who has not been named, is a computer technician based in Nicosia, the country's capital. Police say the man took compromising pictures of the 17-year-old girl and threatened to send the pictures to her email contacts unless she stood naked in front of the webcam, according to reports from Sophos Inc., an anti-virus and anti-spam company with U.S. headquarters in Lynnfield, Mass.

The Trojan that had infected the girl's PC was reportedly sent as an email attachment.

''The last 12 months have seen a dramatic rise in the number of new viruses, worms and Trojan horses designed to spy on innocent users, whether it be via their webcam, intercepting emails, or monitoring key-presses to grab banking passwords,'' says Graham Cluley, senior technology consultant for Sophos. ''Sophos's labs analyze approximately 15 new pieces of malware, which include this kind of sinister payload, every day, compared to five a day a year ago.

''As well as Trojans being used for financial gain, this latest case has highlighted a worrying trend of voyeurism,'' he adds. ''Everyone needs to be extremely careful about their computer security to ensure they do not fall victim to an Internet blackmailer or peeping tom.''

In February, according to Sophos, a computer science student was fined by a Spanish court for a similar offense.