California Code, Probate Code - PROB § 2910

(a) Upon a showing of probable cause to believe that a person is in substantial danger of abuse or neglect and needs a conservator of the person, the estate, or the person and estate for his or her own protection, the public guardian or the county's adult protective services agency may petition for either or both of the orders of the court provided in subdivision (b) in connection with his or her investigation to determine whether a petition for the appointment of the public guardian as conservator of the person, estate, or the person and estate of the person would be necessary or appropriate.

(b) The petition may request either or both of the following orders for the limited purposes of the investigation concerning a person:

(c) Notice of the hearing and a copy of the petition shall be served on the person who is the subject of the investigation in the manner and for the period required by Section 1460 or, on application of the public guardian contained in or accompanying the petition, on an expedited basis in the manner and for the period ordered by the court. The court may dispense with notice of the hearing only on a showing of facts demonstrating an immediate threat of substantial harm to the person if notice is given.