Signs that a person is lying may include overexplaining and repetition, protesting more than seems necessary under the circumstances, becoming evasive and trying to change the subject, and maintaining a still, rigid stance instead of a relaxed, friendly pose. Liars may shuffle their feet and verbally distance themselves from a lie in an unconscious effort to get away from it.
Instinct is a natural tool for spotting liars. Feeling uncomfortable or feeling that something is off about a person telling inconsistent stories and demonstrating outside-the-norm behaviors may be the instinct or gut reaction that rings alarm bells and points to deception.
Police officers and investigators are trained to observe closely during interviews to determine whether or not suspects are answering truthfully. Accomplished liars and scam artists can successfully control facial expressions, behaviors and tone of voice to make lie-detection more difficult, but enforcement officers employ tactics to create holes in stories and uncover lies. An officer may try to trip up a suspect and find discrepancies by asking him to repeat his story from end to beginning. He may also encourage the suspect to provide as much detail as possible. If the suspect is lying and making up details on the spot, it may be possible to prove that the details are false.