An internet paedophile who took control of schoolgirls' computers and blackmailed them into sending explicit images has been jailed for 10 years.
One of Ringland's victims described the ordeal as internet rape
Adrian Ringland, 36, of Lord Haddon Road, Ilkeston, Derbyshire, appeared at Inner London Crown Court on Thursday.
He admitted two charges of indecency with a child, four of hacking, four of blackmail and 10 offences of making indecent photographs of a child.
The offences involved two girls in Britain and one in Canada.
One of the girls said Ringland's level of skill and the power he had over her PC reminded her of the science fiction film Matrix.
Another victim described her ordeal as "internet rape" and spoke of committing suicide, while a third told police she felt as if she was being "stalked", and was so "terrified" that it almost seemed as if the man was in her house.
Ringland also admitted six charges of unlawful intercourse and one of internet grooming.
Thirteen similar charges involving a number of 15-year-old girls were ordered to remain on file.
Lisa Wilding, prosecuting, told the court: "This is a case about manipulation, exploitation and sexual gratification.
"It is a startling tale that will bring home to you the horrors that lurk within the internet and the minds of some individuals who use it."
She said the offences had graphically demonstrated how on-line chat rooms could become "the tool of a paedophile".
The court heard Ringland posed as a teenager in a chat room to gain the girls' trust.
Once he had their e-mails, he used sophisticated software to hack into their systems, moving cursors and in one case opening and closing the CD Rom drawer.
The father-of-two then blackmailed them into sending revealing photographs of themselves.
The court was told that once Ringland felt he had the youngsters under his control he forced them to send more explicit images.
He warned that if they refused, he would send the pictures he already had to their friends, or wipe valuable information from their computers.
A 14-year-old victim in Manitoba, Canada, ignored the threats and told her parents, who alerted the Royal Canadian Mounted Police.
An extensive investigation then traced him back to his home 4,000 miles away.
Unemployed Ringland was arrested by local police and bailed.
During a random police check Ringland was caught having sex with a 14-year-old girl he had groomed on the internet.