New Focus of Airport Safety: Your Smile

Put on a brave face the next time you're at the airport; your expression might be under scrutiny. New security programs at more than a dozen airports are using undercover personnel who watch passengers' faces for indications of criminality. When trying to deceive others, a criminal still exhibits flashes of fear or scorn that officers are being trained to detect.

So-called "behavior detection officers" work as a pair: one of them will approach a suspect while the other watches his or her body language and facial expressions. Homeland Security has high hopes for the program, which is based on a longstanding Israeli operation. (More airport security stories.)