California Code, Code of Civil Procedure - CCP § 516.030

The facts stated in each affidavit filed pursuant to this chapter shall be set forth with particularity. Except where matters are specifically permitted by this chapter to be shown by information and belief, each affidavit shall show affirmatively that the affiant, if sworn as a witness, can testify competently to the facts stated therein. The affiant may be any person, whether or not a party to the action, who has knowledge of the facts. A verified complaint that satisfies the requirements of this section may be used in lieu of or in addition to an ordinary affidavit.