California Code, Probate Code - PROB § 12406

(a) At the hearing, the court shall determine whether the alleged missing person is a person who is presumed to be dead under Section 12401.  The court may receive evidence and consider the affidavits and depositions of persons likely to have seen or heard from or know the whereabouts of the alleged missing person.

(b) If the court is not satisfied that a diligent search or inquiry has been made for the missing person, the court may order the petitioner to conduct a diligent search or inquiry and to report the results.  The court may order the search or inquiry to be made in any manner that the court determines to be advisable, including any or all of the following methods:

(c) The costs of a search ordered by the court pursuant to subdivision (b) shall be paid by the estate of the missing person, but if there is no administration, the court in its discretion may order the petitioner to pay the costs.