I'm a lawyer in Georgia -- California laws may vary substantially. A matter of a bad check is both a criminal matter and a civil matter. The police often chose not to prosecute such cases becase they have "bigger" crimes before them. Anyone who has been given a bad check has the option of going to small claims court, called Magistrate Court in many states, and filing a civil suit against the person who gave them the bad check. Civil suits in Georgia are filed in the county of residence of the defendant rather than the county in which the crime occurred. The civil claim is essentially a breach of contract claim: the check is the contract or promise to pay funds which was not honored because of insufficient funds.