Cal. Code of Civil Procedure § 762.030

(a) If a person required to be named as a defendant is dead and the plaintiff knows of a personal representative, the plaintiff shall join the personal representative as a defendant. (b) If a person required to be named as a defendant is dead, or is believed by the plaintiff to be dead, and the plaintiff knows of no personal representative: (1) The plaintiff shall state these facts in an affidavit filed with the complaint. (2) Where it is stated in the affidvit that such person is dead, the plaintiff may join as defendants “the testate and intestate successors of ____ (naming the deceased person), deceased, and all persons claiming by, through, or under such decedent,” naming them in that manner. (3) Where it is stated in the affidavit that such person is believed to be dead, the plaintiff may join the person as a defendant, and may also join “the testate and intestate successors of ____ (naming the person) believed to be deceased, and all persons claiming by, through, or under such person,” naming them in that manner.