What is the burden of disclosing the identity of an informer?

There is no dispute about the showing which a defendant must make to secure disclosure of an informer's identity. A defendant seeking such disclosure bears the burden of demonstrating that there is "a reasonable possibility that the anonymous informant whose identity is sought could give evidence on the issue of guilt which might result in defendant's exoneration." (People v. Garcia (1967) 67 Cal.2d 830, 840, 64 Cal.Rptr. 110, 116, 434 P.2d 366, 372.)