GOV §68097.1: (a) Whenever an 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

(a) Whenever an 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, district attorney inspector, probation officer, building inspector, firefighter, or city police officer is required as a witness before any court or other tribunal in any civil action or proceeding in connection with a matter regarding an event or transaction which he or she has perceived or investigated in the course of his or her duties, a subpoena requiring his or her attendance may be served by delivering a copy either to the person personally, or by delivering two copies to his or her immediate superior at the public entity by which he or she is employed or an agent designated by that immediate superior to receive that service. (b) Whenever any other state employee or any employee of the trial courts is required as a witness before any court or other tribunal in any civil action or proceeding in connection with a matter, event, or transaction concerning which he or she has expertise gained in the course of his or her duties, a subpoena requiring his or her attendance may be served by delivering a copy either to the person personally or by delivering two copies to his or her immediate superior or agent designated by that immediate superior to receive that service. (c) The attendance of any person described in subdivisions (a) and (b) may be required pursuant to this section only in accordance with Section 1989 of the Code of Civil Procedure. (d) As used in this section and in Sections 68097.2 and 68097.5, “tribunal” means any person or body before whom or which attendance of witnesses may be required by subpoena, including an arbitrator in arbitration proceedings.