Movie: The Lives of Others

I just watched a dvd, "The Lives of Others", a German movie. Highly recommended. The male protagonist in the movie was a captain working in the secret police of the old Berlin. He was teaching a lesson to the new trainees on how to identify an innocent person or a guilty person. He mentioned the best way to identify a guilty person is non stop interrogation. Ask the subject the same question again and again. Listen to the answer. If the answer is the same; word by word; every time, the person is a liar. A truthful person will reformulate the answer. Only a liar prepare the answer, so that he can fall back on the prepared answer when under pressure.

The reason for non stop interrogation is not just to tire the person physically, but most importantly, to make him mentally exhausted. When a person is mentally tired, he will tend to reveal information that will incriminate himself or the guilty parties. This is also the best time when the subject is at his most vulnerable state. That's why it is important for an investigator to be physically and mentally fit so that he will not miss out all these important "leaks". Once you miss them, you miss them forever.