California Probate Code Section 12403

(a) If the missing person was a resident of this state when last seen or heard from, the superior court of the county of the person`s last known place of residence has jurisdiction for the purposes of this part. (b) If the missing person was a nonresident of this state when last seen or heard from, the superior court of a county where real property of the missing person is located, or of a county where personal property is located if the missing person has no real property in this state, has jurisdiction for the purposes of this part.