California Code, Code of Civil Procedure - CCP § 1021.7

In any action for damages arising out of the performance of a peace officer's duties, brought against a peace officer, as defined in Chapter 4.5 (commencing with Section 830) of Title 3 of Part 2 of the Penal Code, or against a public entity employing a peace officer or in an action for libel or slander brought pursuant to Section 45 or 46 of the Civil Code, the court may, in its discretion, award reasonable attorney's fees to the defendant or defendants as part of the costs, upon a finding by the court that the action was not filed or maintained in good faith and with reasonable cause.