What is the test for establishing that a citizen informant is reliable?

It may therefore be stated as a general proposition that private citizens who are witnesses to or victims of a criminal act, absent some circumstance that would cast doubt upon their information, should be considered reliable. This does not, of course, dispense with the requirement that the informant--whether citizen or otherwise--furnish underlying facts sufficiently detailed to cause a reasonable person to believe that a crime had been committed and the named suspect that the perpetrator; and the rule also presupposes that the police be aware of the identity of the person providing the information and of his status as a true citizen informant. (People v. Abbott (1970) 3 Cal.App.3d 966, 970--971, 84 Cal.Rptr. 40.) In short, probable cause will not be provided by conclusionary information or anonymous informants, but neither a previous demonstration of reliability nor subsequent corroboration is ordinarily necessary when witnesses to or victims of criminal activities report their observations in detail to the authorities. ⁴