Cal. Civil Code § 1798.41

(a) Except as provided in subdivision (c), if the agency determines that information requested pursuant to Section 1798.34 is exempt from access, it shall inform the individual in writing of the agency’s finding that disclosure is not required by law. (b) Except as provided in subdivision (c), each agency shall conduct a review of its determination that particular information is exempt from access pursuant to Section 1798.40, within 30 days from the receipt of a request by an individual directly affected by the determination, and inform the individual in writing of the findings of the review. The review shall be conducted by the head of the agency or an official specifically designated by the head of the agency. (c) If the agency believes that compliance with subdivision (a) would seriously interfere with attempts to apprehend persons who are wanted for committing a crime or attempts to prevent the commission of a crime or would endanger the life of an informant or other person submitting information contained in the record, it may petition the presiding judge of the superior court of the county in which the record is maintained to issue an ex parte order authorizing the agency to respond to the individual that no record is maintained. All proceedings before the court shall be in camera. If the presiding judge finds that there are reasonable grounds to believe that compliance with subdivision (a) will seriously interfere with attempts to apprehend persons who are wanted for committing a crime or attempts to prevent the commission of a crime or will endanger the life of an informant or other person submitting information contained in the record, the judge shall issue an order authorizing the agency to respond to the individual that no record is maintained by the agency. The order shall not be issued for longer than 30 days but can be renewed at 30-day intervals. If a request pursuant to this section is received after the expiration of the order, the agency must either respond pursuant to subdivision (a) or seek a new order pursuant to this subdivision.