Cal. Gov. Code § 68097.5
No employee of the Department of Justice who is a peace officer or an analyst in a technical field, peace officer of the Department of the California Highway Patrol, peace officer member of the State Fire Marshal's office, sheriff, deputy sheriff, marshal, deputy marshal, firefighter, or city police officer shall be ordered to return by the court for subsequent proceedings beyond the day stated in the subpoena referred to in Sections 68097.1, 68097.2, 68097.3 and 68097.4, or the day upon which the witness appeared pursuant to the provisions of Section 68097.9, unless the party at whose request the subpoena was issued or the party at whose request the witness is ordered to return, shall first tender to the public entity by which the witness is employed the same sum required to be tendered for the issuance of a subpoena in the first instance.
Ca. Gov. Code § 68097.5