Concerns as face recognition tech used to 'identify' criminals

What can your face say about you? Face recognition technology can pick up on things like your age, gender and maybe even your mood. Now, two researchers say it could even tell whether you're a criminal. They are claiming to have developed a system that, when shown a series of faces it has never encountered before, can pick out the ones belonging to convicted criminals. But other researchers have criticised the results, and say the work raises ethical questions over what face recognition technology can and should be used to detect.