An international hunt is under way for a prolific paedophile after police experts unscrambled internet images of him that had been digitally altered to disguise his identity.

Interpol has made an unprecedented global appeal to catch the man, code-named Vico, who is shown sexually abusing children in about 200 images posted on the web. The photographs feature the abuse of 12 young boys aged between 6 and their early teens. It has been established that the images were taken in Vietnam and Cambodia.

The Interpol hunt across 186 countries has so far failed to identify the man, thought to be of European origin. Police have released a series of identifiable images in an attempt to get public help to track him down. The original photographs were digitally altered to create a swirling effect that disguised the man’s face. But specialists from the German federal police agency, the Bundeskriminalamt, worked with the Trafficking in Human Beings Unit of Interpol to unscramble the pictures.

General Ronald Noble, the Interpol Secretary, said: “For years images of this man sexually abusing children have been circulating on the internet. We have tried all other means to identify and to bring him to justice but we are now convinced that without the public’s help this sexual predator could continue to rape and sexually abuse young children.”

Michael Moran, a Criminal Intelligence Officer at Interpol on secondment from the Irish police, said: “The swirling effect used in the images can be found in any high-end photographic editing software. If the image was twisted clockwise, the German team twisted it counter-clockwise. If you can identify the middle of the picture, then you can use the same filter yourself to do the same thing.”

Anders Persson, a Swedish police officer seconded to Interpol, said that a child abuser seeking contact with other like-minded individuals on the web would sometimes post pictures of himself in the act of abuse to prove that he was a hard-core paedophile.

German police first found pictures of the man in 2004. They traced him to a Vietnamese hotel though advertising material that could be seen on a bedside table in some of the pictures. Checks against passport photos of people staying at the hotel at the time drew a blank. Other photos were taken at outdoor locations in Cambodia that were recognised by police there.

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