Laws written by Congress and state legislators that make certain behavior illegal and punishable by fines and/or imprisonment. Criminal law also includes decisions by appellate courts that define crimes and regulate criminal procedure in the absence of clear legislated rules. By contrast, civil laws are not punishable by imprisonment. In order to be found guilty of a criminal law, the prosecution must show that the defendant intended to act as he did; in civil law, you may sometimes be responsible for your actions even though you did not intend the consequences. For example, civil law makes you financially responsible for a car accident you caused but didn't intend.