A lie detector, also known as a polygraph, is a machine that measures a person’s physiological responses when asked a question. The machine can measure your breathing, blood pressure, and perspiration. The accuracy of lie detector tests is highly debated. What if you are giving a truthful answer, but you are simply very nervous about being questioned?
If police are asking you to take a lie detector test it usually means they don’t have a great case against you, and they are trying to gather more evidence needed to charge and convict you. The police officer may use the information in its investigation. However, the results of the test may or may not be admissible in court, depending on various factors. Much depends on whether you are in state or federal court, and in which jurisdiction.
If a police officer asks you to take a lie detector test, you should immediately consult a lawyer. The police officer can use that information in his investigation and it could be used against you in a court of law.