California Code, Government Code - GOV § 27498

(a) The coroner may issue subpoenas for witnesses, returnable forthwith or at such time and place as the coroner appoints, which may be served by any competent person. The coroner may also require any such witness to bring with him or her any books, records, documents, or other things under the control of the witness which, in the opinion of the coroner, are necessary to the conduct of the inquest and as a further aid in determining the circumstances, manner, and cause of death of the decedent. To enforce the provisions of this section, the coroner may issue subpoenas duces tecum in accordance with Section 1985 of the Code of Civil Procedure. In case of failure of a witness to attend, and in the case of a subpoena duces tecum, for the failure to produce the items set forth therein, the coroner, or the coroner's authorized deputy, issuing the subpoena upon proof of service thereof, and the failure of the witness, may certify the facts to the superior court in the county where the proceedings are held. The court shall thereupon issue an order directing the person to appear before the court and show cause why he or she should not be ordered to comply. The order and a copy of the certified statement shall be served on the person. Thereafter the court shall have jursidiction  1 of the matter. The same proceedings shall be had, the same penalties may be imposed and the person charged may purge himself or herself of the contempt in the same way as in the case of a person who has committed a contempt in the trial of a civil action before a superior court. The items set forth on the subpoena duces tecum shall not be made public unless an inquest is held.

(b) Any books, records, documents, or other things under the control of a law enforcement agency, subpoenaed pursuant to subdivision (a), shall not themselves be made a part of the record in any coroner's inquest without the written consent of the law enforcement agency, when such inquest pertains to a death caused by a police officer.