What is the test for establishing the credibility of an informant in a criminal case?

The informant must establish his or her reliability and that the information has a factual basis. ( Illinois v. Gates, supra, 462 U.S. at p. 230, 103 S.Ct. 2317.) "The rule that the affiant must demonstrate a tipster's probable reliability or credibility arises not only from the usual distrust of hearsay evidence but also from an assumption that information provided by customary police sources is inherently suspect." ( People v. Kurland (1980) 28 Cal.3d 376, 392, 168 Cal.Rptr. 667, 618 P.2d 213.) The type of informant, the type of evidence (hearsay or personal knowledge) and whether the evidence is corroborated all work together to determine whether probable cause exists. The reliability of an informant can be confirmed in a variety of ways, "as by corroboration of the information received [citations], the informant's previous record of accuracy in similar situations [citation], or indications that the informant has spoken against penal interest. [Citation.]" ( Ibid. )