How can you tell when a person is lying?

A new device called AVATAR is being developed by scientists and engineers to help law enforcement officials determine whether or not a suspect is lying. The idea behind it has gained momentum as various labs have zeroed in on how the human face, or body, changes if a person is lying. For example, researchers at Temple University Hospital used brain imaging equipment to show that parts of the brain light up when a person lies.
March 3, 2011 | Fox29