California Code, Code of Civil Procedure - CCP § 801.3

The complaint shall include as defendants to the action (a) all persons known to the plaintiff owning or claiming an interest under such public improvement assessment, bond or certificate of sale; (b) the payee, as shown by the bond representing the assessment, if any; (c) the owner of the special assessment or certificate of sale, if any, and any person claiming an interest therein, as shown by the records of the treasurer, street superintendent or other public official who is the custodian of the funds to be collected thereon or who issued such certificate of sale, and (d) such treasurer, street superintendent or other public official. If any person owning or claiming an interest under such assessment, bond or certificate of sale is known to be dead, the heirs and devisees of such person may be sued as: “the heirs and devisees of” said person, naming him, or if such person is believed to be dead and such belief is alleged in the complaint on information and belief then the heirs and devisees of such person may also be sued as “the heirs and devisees” of said person, naming him, provided that such person is also named as a defendant.