The prosecution can satisfy its burden of proof at a suppression hearing by presenting the investigating officers’ affidavit in lieu of live testimony. Such a procedure is permitted by Code of Civil Procedure 2009 (permitting use of affidavits in connection with motions) and Penal Code section 1102 (generally applying the rules of evidence in civil actions to criminal cases). The sworn affidavit of the investigating officer, relating facts of personal knowledge and setting forth his or her relevant training and experience, combined with the defendant’s right to call the affiant for cross-examination at the suppression hearing sufficiently protects the defendant’s due process rights.