Aguilar-Spinelli Test

The Aguilar-Spinelli test is a two-pronged test still used in some state courts and formerly used by the U.S. Supreme Court to determine whether an informant provides sufficient probable cause for a warrant. Under the test, law enforcement officials must show both the veracity and basis of knowledge of the informant before establishing probable cause. This means that law enforcement officers have to show a neutral magistrate that an informant is reliable and that the informant had access to or a specific basis for the information.

The U.S. Supreme Court developed the test from its decisions in Aguilar v. Texas (1964) and Spinelli v. United States (1969). The Court abandoned the Aguilar-Spinelli test in favor of the more law-enforcement-friendly “totality of the circumstances” test in Illinois v. Gates (1983). In Gates, Justice William H. Rehnquist recognized that the reliability, veracity, and the basis of knowledge of an informant were all relevant factors, but the absence of one should not void a warrant for lack of probable cause. He wrote that the “totality-of-the-circumstances approach is far more consistent with our prior treatment of probable cause than is any rigid demand that specific ‘tests’ be satisfied by every informant's tip.”

Many state high courts have rejected the Gates “totality of the circumstances” approach and found that their state constitutional provisions regarding unreasonable searches and seizures require an application of the Aguilar-Spinelli test. For example, the Tennessee Supreme Court rejected the Gates ruling in State v. Jacumin (Tenn. 1989), writing that “the pr inciples developed under Aguilar v. Texas and Spinelli v. United States, if not applied hypertechnically, provide a more appropriate structure for probable cause inquiries incident to the issuance of a search warrant than does Gates.”