A dream involving the police means you feel guilty for not honoring a promise or obligation.
If you dream that you are a police officer, this represents your own sense of morality and conscience. Your unconscious mind may be trying to guide you down a straight path.
If you dream of being an undercover cop, you are feeling guilty about your past actions.
To dream that you or others are being chased by the police, suggests that you are trying to avoid responsibility for something.