How to spot a liar: coach to crime fighters reveals common tics

Bill Clinton's head is bowed, hands masking his mouth, as his inquisitor asks: "If Monica Lewinsky said that while you were in the Oval Office area you touched her breasts, would she be lying?" The US president blinks rapidly as he pauses, then leans back, breathes deeply, and delivers a textbook politician's response: "Let me say something about all this."

American deception expert Clark Freshman is showing the video clip, taken from Clinton's 1998 testimony in the sex scandal that led to his impeachment, to make a point.

"It's a 'yes' or 'no' answer, but he doesn't really answer the question," he tells a gathering of police officers, barristers, lawyers, and officials from the Monetary Authority and Department of Justice. All have a professional interest in detecting deceit, and are attending Freshman's seminar on the art and science of lie detection, organised by The Forensics Company, a Hong Kong-based consultancy.

Freshman, a professor at University of California, Hastings College of Law, is highly sought after for his expertise in lie detection and non-verbal communication picked up over decades working in law. He has also worked with US psychologist Paul Ekman, with whom he collaborated on the Fox TV courtroom drama, .

As he replays the recording in slow motion, he points out facial expressions indicating that Clinton, if not lying, is certainly feeling uncomfortable.

Asked if he kissed the intern's breasts, his nose wrinkles in the bat of an eye. That's a sign of disgust, Freshman says. Asked if he used a cigar on her as a sexual aid, his eyes pop wide open in surprise so rapidly it's easy to miss. Clinton replies repeatedly that he stands by his statement: he did not have "sexual relations" with Lewinsky. (He later admitted that he did; it had been a matter of definition.)