Spinelli v. United States

Spinelli v. United States was a 1969 decision by the United States Supreme Court that required a magistrate to be informed of the "underlying circumstances from which the informant had concluded" that a crime had been committed before issuing a search warrant.

Along with Aguilar v. Texas, Spinelli established the Aguilar–Spinelli test, a judicial guideline for evaluating the validity of a search warrant based on information provided by a confidential informant or an anonymous tip. Aguilar-Spinelli was, in turn, replaced by a "totality of the circumstances" test with Illinois v. Gates in 1983.