A British media student who was arrested while luring his third underage victim for sex has become the first paedophile in the UK to be caught by an international online police taskforce.

Lee Costi, 21, who had links with paedophiles in Poland and Hawaii, had already groomed and then had sex with two other young girls, aged 13 and 14, through internet chatrooms when he was caught trying to ensnare the 14-year-old girl online.

Detectives were tipped off when the girl told her mother, and the family e-mailed the Virtual Global Taskforce (VGT) about Costi's indecent suggestions. The VGT, a multi-national organisation set up to tackle internet child abuse, invites youngsters to go online to report suspicious grooming activity.

The organisation is monitored 24 hours a day by police agencies all over the world and they passed her email to the Paedophile Online Investigation Team, part of the National Crime Squad, who in turn contacted Nottinghamshire police.

Costi, from Haslemere, Surrey, was arrested after arranging to meet the 14-year-old at Nottingham railway station.

He was sentenced today to nine years for having sex with the girls, for inciting his third victim to perform sex acts over her computer web cam, and for having more than 40 indecent images of children. One of the images was said to be of the most serious level of abuse of a young girl.

Officers also found 355 chat log files detailing his conversations with young girls in chatrooms, mostly outlining his interest in underage sex, Nottingham Crown court heard. They believe there may be other victims too scared to come forward.

Detective Superintendent Jackie Alexander, the head of the sexual exploitation unit for Nottinghamshire police, said: "We were fortunate that a young Nottinghamshire girl was brave enough to tell her parents.

"It can be very difficult for them. They can realise their foolishness after the event but do not go on to report it."

She added: "There may be other girls out there in a similar position. It is impossible to say how many victims there may have been."

Grace Hall, prosecuting, told the court that the girl had been flattered by Costi’s attention and wanted to impress her friends with her online relationship. "She says she complied (with Costi’s requests) so that she could tell her friends so they would not continue to think of her as boring."

Police were lying in wait to catch Costi as he arrived for the train station meeting in January last year, but he did not show up. Instead, computer records followed by the taskforce and handed to police traced him to his parents’ house.

The older of Costi’s first two victims spent the night with him in a Swindon hotel in August 2004, while the younger teenager met and had sex with him in January last year in an alleyway near London’s Waterloo Station.

Mrs Alexander revealed that the force analysis of Costi’s PC had identified two other paedophiles, one in Poland and one in Hawaii, who had links with Costi.

The international scheme invites youngsters to go online to report suspicious grooming activity.

Reports are monitored by Interpol and forces across the world, including the Child Exploitation and Online Protection (CEOP) Centre in the UK, the Royal Canadian Mounted Police, Australian High Tech Crime Centre and the US Department of Homeland Security.

Jim Gamble, head of the VGT board and Chief Executive of CEOP, said: "This young girl has not only prevented further harm to herself and to other potential victims, but has also saved countless other children who had not got to this stage yet.

"Child sex abuse is one of the worst crimes imaginable, and while the internet is a very vibrant environment for children and young people, it is also a place where people have to be careful. If in any doubt, members of the public can report inappropriate behaviour by clicking on our website and then rely on the police to take matters further."

The VGT website address is virtualglobaltaskforce.com.

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