California Code, Government Code - GOV § 6204

(a) For purposes of this chapter, the following definitions shall apply:

(b) Whenever the secretary, in consultation with the archivist, has reasonable grounds to believe that a record belonging to the state or a local agency is in the possession of a person, organization, or institution not authorized by law to possess that record, the secretary may issue a written notice demanding that person, organization, or institution to do either of the following within 20 calendar days of receiving the notice:

(c) The notice and demand issued pursuant to subdivision (b) shall identify the record claimed to belong to the state or local agency with reasonable specificity, and shall state that the secretary is authorized to take legal action to recover the record if the person, organization, or institution fails to respond in writing within the required time or does not adequately demonstrate that the record does not belong to the state or a local agency.

(d) The secretary shall send the notice and demand specified in subdivision (b) by certified or registered mail, return receipt requested.

(e) When a record is returned pursuant to paragraph (1) of subdivision (b), upon the request of the person, organization, or institution that returned the record, the secretary or a local agency that receives the record shall issue to that person, organization, or institution a copy or digital image of the record, which shall be certified as a true copy of the record that was returned to the state or local agency, and dated on the same day the record was returned.