Cal. Civ. Code § 910-2-6-4

Sec. 4. (a) Upon filing a complaint under section 2 of this rule, the ICRC will initiate an investigation. The purposes of an investigation are as follows:
(1) To obtain information concerning the events or transactions that relate to the alleged discriminatory housing practice identified in the complaint.
(2) To document policies or practices of the respondent involved in the alleged discriminatory housing practice raised in the complaint.
(3) To develop factual data necessary for the director to make a determination under section 6(a) of this rule whether reasonable cause exists to believe that a discriminatory housing practice has occurred, or is about to occur, and to take other actions provided under this section.

(b) Upon the written direction of the director, the ICRC may initiate an investigation of housing practices to determine whether a complaint should be filed under section 2 of this rule. Such an investigation will be conducted in accordance with the procedures described under this section.
(c) Where the director determines that:
(1) the alleged discriminatory practices contained in a complaint are pervasive or institutional in nature; or
(2) processing the complaint will:
(A) involve complex issues or novel questions of fact or law; or
(B) affect a large number of persons;

the director may identify the complaint for systemic processing. This determination can be based on the face of the complaint or on information gathered in connection with an investigation. Systemic investigations may focus not only on documenting facts involved in the alleged discriminatory housing practice that is the subject of the complaint but also on reviewing other policies and procedures related to matters under investigation to make sure that they also comply with the nondiscrimination requirements of IC 22-9.5.

(d) In conducting an investigation under this section, the ICRC will seek the voluntary cooperation of all persons to obtain access to premises, records, documents, individuals, and other possible sources of information:
(1) to examine, record, and copy necessary materials; and
(2) to take and record testimony or statements of persons reasonably necessary for the furtherance of the investigation.
The ICRC may conduct discovery in aid of the investigation by the same methods and to the same extent that parties may conduct discovery in an administrative proceeding under 910 IAC 2-7, except that the ICRC shall have the power to issue subpoenas described in 910 IAC 2-7-6(a) in support of the investigation. An administrative law judge, upon motion sufficiently supported and due to exceptional circumstances, may grant to any party the use of any discovery provision under 910 IAC 2-7 at any time after the filing of a complaint.

(e) The ICRC, in processing complaints, may seek the cooperation and utilize the services of federal or substantially equivalent local agencies, including any substantially equivalent local agency having regulatory or supervisory authority over financial institutions.
(f) The investigation shall remain open until the reasonable cause determination is made under section 6(a) of this rule or a conciliation agreement is executed and approved under section 5(b) of this rule. Unless it is impracticable to do so, the ICRC shall complete the investigation of the alleged discriminatory housing practice within one hundred (100) days of filing the complaint (or where the ICRC reactivates the complaint, within one hundred (100) days after service of the notice of reactivation under section 3(d) of this rule). If the ICRC is unable to complete the investigation within the one hundred (100) day period, the ICRC shall notify the aggrieved person and the respondent, by certified mail or personal service, of the reasons for the delay.
(g) At the end of each investigation under this section, the ICRC shall prepare a final investigative report. The investigative report shall contain the following:
(1) The names and dates of contacts with witnesses.
(2) A summary and the dates of correspondence and other contacts with the aggrieved person and the respondent.
(3) A summary description of other pertinent records.
(4) A summary of witness statements.
(5) Answers to interrogatories.
A final investigative report may be amended at any time if additional evidence is discovered.

(h) Notwithstanding the prohibitions and requirements with respect to disclosure of information contained in section 5(j) of this rule, the ICRC will make information derived from an investigation, including the final investigative report, available to the aggrieved person and the respondent. Following the completion of investigation, the ICRC shall notify the aggrieved person and the respondent that the final investigation report is complete and will be provided upon request.