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LONDON - Facial recognition technology being considered for London's 2012 Games is getting a workout in the wake of Britain's riots, a law enforcement official told The Associated Press on Thursday, with officers feeding photographs of suspects through Scotland Yard's newly updated face-matching program.

The official said that the Metropolitan Police's sophisticated software was being used to help find those suspected of being involved in the worst unrest the force has faced in a generation, although he cautioned that police had a host of other strategies at their disposal.

"A lot of tools are being used to hunt down these criminals, and that's just one of them," the official said on condition of anonymity because he was not authorized to speak about an ongoing investigation. "The issue is that you have to have a good picture of a suspect and it is only useful if you have something to match it against. In other words, the suspect already has to have a previous criminal record."

A press officer with Scotland Yard — who also spoke anonymously, in line with force policy — confirmed Thursday that facial recognition technology was at the police's disposal, although he gave few other details. He said that generally the technology would only be used to help identify those suspected of serious crimes, such as assault, and that in most cases disseminating photographs to the general public remains a far cheaper and more effective way of identifying people.

To that end the police have released two dozen photos and videos to the picture-sharing website Flickr, where they've already gathered more than 400,000 hits. Some of those photographs have also been published by Britain's brash tabloid press. The Sun recently plastered them across its front page, along with a headline urging readers to report looters to the police.

The photographs on Flickr are mainly grainy images pulled from closed circuit television cameras, which may not be of much use to face-matching software. But other pictures — taken by police surveillance teams, published in the media or snapped by passers-by — could provide higher-resolution images.

The facial-recognition technology used by police treats the human face like a grid, measuring the distance between a person's nose, eyes, lips and other features. It has recently been upgraded, according to an article published last year in Scotland Yard's bimonthly magazine, "The Job."

According to the March 2010 article, the new program has been shown to work far better than older versions of the technology. One expert cited by the article said it had shown promise in matching high-quality, face-on shots taken from surveillance photographs, mobile phones, passports or even off the Internet.

Facial recognition technology is already widely employed by free-to-use websites such as Facebook and Google Inc.'s Picasa photo-sharing program.

Such programs have been of increasing interest to authorities as well. A person with the Olympic planning committee recently told the AP that facial recognition software was being considered for use during the Olympic Games.

He spoke on condition of anonymity because of the sensitivity of security preparations.