If you’ve been accused of a crime and know you’re innocent, you might be tempted to agree to a lie detector test, also known as a polygraph. A law enforcement officer may ask you to take the test. You may wish to prove your innocence by submitting to one, but it is always better to seek legal advice first.
If you’re accused of a crime in California, the results of a lie detector are not permitted into evidence. That is not to say taking one will not harm your defense. It could well do so.
Why you should not take a polygraph
You expect law enforcement to conduct an impartial investigation and only seek the truth. However, law enforcement may use leading questions to try to trick you into giving them something they can use against you. They might even take what you say and twist its meaning to suggest you are admitting to the crime. If you just stay silent and refuse to take the test, you do not give them that opportunity,
It’s rarely in your best interest to agree to one. You cannot even rely on a negative test to back you up, as the only way to have the results presented to a jury is if you, your defense, and the prosecution all agree to it. The prosecution might refuse if they believe it harms their case against you.
Suppose you’re being investigated for a crime and are considering submitting to a polygraph. In that case, you may want to become familiar with their reliability and seek appropriate defense counsel first.