A secret computer program that helps track down paedophiles on the Internet has been created by Google Inc.
The program, which was developed by scientists who devised some of the Internet search engine's most popular services -including its photo library Picasa and popular YouTube, lets investigators quickly trawl through a suspect's computer and find shocking images - even when concealed in a seemingly innocent video.
They can also match a child's face shown in a video to similar images discovered around the world, reports News of the World.
The system can also recognise background scenes in an abuse clip.
The sophisticated system also spots matches in an image's pixels after paedophiles have tried to retouch or alter it.
The program is the brainchild of Shumeet Baluja, a senior researcher at Google's Washington office.