California Code, Vehicle Code - VEH § 6172

Upon expiration of a reasonable time for the completion of the examination, which in no event shall exceed 30 days from the date of service of the notice of request or return of the motor vehicle as provided in Section 6171, the property shall be released to the person making that request after satisfactory proof of the person's entitlement to the possession.  Notwithstanding the foregoing, upon ex parte application by either party with notice to the other, the court may grant additional time for the examination or order retention of the motor vehicle if it determines that either is necessary to further the interests of justice;  however, this provision shall not be construed to require a noticed hearing.