Also known as: Aguilar-Spinelli test · Aguilar Spinelli · Aguilar-Spinelli rule · two-prong test · informant credibility test
Written by attorneys · grounded in primary & secondary sources — see below
A two-prong test for determining whether an informant's tip supplies probable cause to support issuance of a search warrant. The test requires a magistrate to find both that the informant is credible or reliable and that the informant obtained the information in a reliable way.
Police sought a warrant based on a tip from a first-time informant about drugs in a specific apartment. The magistrate assessed the informant's past reliability and how the informant learned the details. The court applied the two-prong test to decide whether probable cause existed.
Police received an anonymous letter detailing a couple's drug trafficking plans and travel itinerary. Officers verified the travel details and observed suspicious behavior at the airport. The court evaluated whether the corroborated facts supplied the missing credibility and basis-of-knowledge elements under the two-prong test.
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Officers obtained a warrant relying on a confidential informant's report of observing narcotics sales at a residence. The defense challenged the warrant by questioning the informant's track record and how the observations occurred. The court applied the two-prong test to determine if probable cause was properly established.
The first prong examines the informant's credibility or reliability. The second prong examines the basis of the informant's knowledge.
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The Court found the two-prong test too rigid and inconsistent with the flexible, common-sense approach traditionally used for probable cause. It adopted a totality-of-the-circumstances test instead.
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The standards were abandoned as a mandatory test, but courts may still consider the informant's credibility and basis of knowledge as relevant factors within the totality-of-the-circumstances analysis.
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…Concurring opinions Concurring in part and dissenting in part — Justice Brennan Justice Brennan agreed that the two-prong test was appropriate but disagreed with the majority's application of the prejudice prong in capital cases. He would require a somewhat different showing of prejudice in the capital sentencing…