Aguilar v. Texas

Aguilar v. Texas was a 1964 decision by the United States Supreme Court, which held that “[a]lthough an affidavit supporting a search warrant may be based on hearsay information and need not reflect the direct personal observations of the affiant, the magistrate must be informed of some of the underlying circumstances relied on by the person providing the information and some of the underlying circumstances from which the affiant concluded that the informant, whose identity was not disclosed, was creditable or his information reliable.”

Along with Spinelli v. United States, Aguilar 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.