Illinois v. Gates

The facts failed to meet the Aguilar-Spinelli “two-pronged test” of (1) revealing the informant’s “basis of knowledge” and (2) providing sufficient facts to establish either the informant’s “veracity” or the “reliability” of the informant’s report. However, the Court held that the overly rigid Aguilar-Spinelli test should be set aside when a common-sense test is more useful in determining whether “probable cause” exists. The task of the issuing magistrate is simply to make a practical, common-sense decision whether, given all the circumstances set forth in the affidavit, there is a fair probability that contraband or evidence of a crime will be found in a particular place. The duty of a reviewing court is to ensure that the magistrate has a substantial basis for concluding that probable cause existed. Therefore, the Court created the “totality of the circumstances” test to replace (or supplement) the Aguilar-Spinelli test. In this case, the totality of the circumstances indicated that the information was truthful and created probable cause for the issuance of a search warrant.