California Code, Welfare and Institutions Code - WIC § 4427

When the department has reason to believe that any person held in custody as developmentally disabled is wrongfully deprived of his liberty, or is cruelly or negligently treated, or that inadequate provision is made for the skillful medical care, proper supervision, and safekeeping of any such person, it may ascertain the facts. It may issue compulsory process for the attendance of witnesses and the production of papers, and may exercise the powers conferred upon a referee in a superior court. It may make such orders for the care and treatment of such person as it deems proper.

Whenever the department undertakes an investigation into the general management and administration of any establishment or place of detention for the developmentally disabled, it may give notice of such investigation to the Attorney General, who shall appear personally or by deputy, to examine witnesses in attendance and to assist the department in the exercise of the powers conferred upon it in this code.

The department may at any time cause the patients of any county or city almshouse to be visited and examined, in order to ascertain if developmentally disabled persons are kept therein.