In Illinois v. Gates (1983) 462 U.S. 213, the United States Supreme Court explained the standard by which a magistrate must determine whether an affidavit is sufficient to establish probable cause. The Court explained: "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 before him, including the 'veracity,' reliability, and 'basis of knowledge' of persons supplying hearsay information, there is a fair probability that contraband or evidence of a crime will be found in a particular place. And the duty of a reviewing court is simply to ensure that the magistrate had a 'substantial basis for . . . concluding' that probable cause existed. " The Court stated, "A magistrate's 'determination of probable cause should be paid great deference by reviewing courts.' " (Id. at p. 236.) The high court rejected rigid adherence to the 'two pronged' probable cause test described in Aguilar v. Texas (1964) 378 U.S. 108, and Spinelli v. United States (1969) 393 U.S. 410. Instead, the court embraced a 'totality of the circumstances' approach under which 'the task of the issuing magistrate is simply to make a practical, commonsense decision whether, given all the circumstances set forth in the affidavit before him, including the "veracity" and "basis of knowledge" of persons supplying hearsay information, there is a fair probability that contraband or evidence of a crime will be found in a particular place.' ( Gates, supra, 462 U.S. at p. 238) The court observed that 'probable cause is a fluid concept--turning on the assessment of probabilities in particular factual contexts--not readily, or even usefully, reduced to a neat set of legal rules.' (Gates, supra, 462 U.S. at p. 232)