PARIS — He apparently traveled the world sexually abusing young boys, but remained unidentifiable — until now.
Police in Europe have unscrambled digitally altered images found on the Internet to reveal the face of a man shown abusing boys in Vietnam and Cambodia.
Interpol released four reconstructed photos of the suspected pedophile on Monday in an unprecedented public appeal for help, hoping that someone, somewhere, will recognize the man whose identity and nationality remain a mystery.
The response has been encouraging: about 200 messages in just over 12 hours, Interpol said.
But the decision to unmask him is not without risk: Tipping criminals off to the techniques that police have at their disposal could also prompt them to better hide their identities.
Interpol said 12 boys, apparently ranging in age from 6 to early teens, appeared in about 200 photographs posted on the Internet. But the face of the man inflicting the abuse was disguised in a digital whirl.
Using techniques that neither they nor Interpol would discuss, German police produced identifiable images of the man from the original pictures. The reconstructed photos showed a white man who looked to be in his 30s, with uncombed short brown hair. One showed him wearing glasses, in another he smiled, and another showed that he has a hairy chest. Interpol posted the images on its Web site.
Anders Persson, a Swedish police officer assigned to Interpol's human trafficking unit who oversees its database of images of child abuse, said releasing the photos sent "a quite clear message" to criminals that they can be identified through Web postings.
"We have a lot of responses and they are coming from all over the world," Persson said in a telephone interview.
Some of the responses included detailed information such as names and addresses, he said. Others are sightings of people met on vacation.
Interpol forwards detailed information to the countries concerned so police can check, Persson said. Local police are also getting responses to the appeal, he added.
Persson said he personally had opposed making the photos public because it demonstrated to criminals that police can unscramble pictures. But that consideration and the risk that the man could face public humiliation or even violence now that he is recognizable were outweighed by the desire to protect other children from abuse.
"It was a long discussion," Persson said. "We can't just sit here and do nothing. We have exhausted all possibilities within police work to find this man. ... This was the last step."
Interpol said the reconstructed images were produced by Germany's Bundeskriminalamt, or BKA, police force. Contacted separately by The Associated Press, a BKA spokesman said the agency did not want to give details of the process used by its image processing expert "because we do not want to give criminals the opportunity to adjust to the techniques we are using."
The techniques do not appear very complicated: the AP produced an almost recognizable image of the man from the blurred photo that Interpol also distributed, in just a few minutes using commercially available computer software for editing photographs. The AP image was not as clear as Interpol's but still showed the outlines of a face rather than a mere blur.
"Techniques are always developing. What is impossible today is possible tomorrow," Persson said. "There were several attempts to clear the face. ... We are sure that you can't get better pictures, and the people in his neighborhood — family friends, colleagues, whatever — they will recognize him."
Persson said one of the 200 pictures showed the name of a hotel in Vietnam, but police checks of the guest register turned up no clues. Cambodian police recognized locations in other photos.
The photos must date from before December 2004, when they were found on the Internet, and some were digitally stamped as having been taken in 2002 and 2003, Persson said.
The 12 boys have not been located, he added.
Interpol had already circulated photos of the man to police around the world but failed to identify him. Persson said he believes Interpol obtained the first photos in the spring of 2005, then more came in.
"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," Interpol's secretary general, Ronald K. Noble, said in a statement.
"We have very good reason to believe that he travels the world in order to sexually abuse and exploit vulnerable children," Noble said.
Distinguishing marks on his body will help police be sure that they have their man if he is eventually caught, Persson said. He did not say what these marks were but said they would be "the final proof if he is the right guy or not."
Interpol asked people who recognize the man or who have other information to contact police or the Interpol bureau in their country. It urged them not to take any direct action themselves.
On the Net: www.interpol.int