Spinelli v. United States

Background

William Spinelli, accused of running a telephone bookmaking operation and convicted under a federal travel-for-gambling law, challenged the search warrant that produced evidence against him. The FBI affidavit relied on an anonymous informant who said Spinelli used two phone numbers for gambling, plus FBI surveillance showing repeated trips to an apartment and telephone-company records. Lower courts disagreed about the warrant: one judge said Spinelli lacked standing, a panel found no probable cause, an en banc court sustained the warrant by 6–2, and the Supreme Court agreed to review only the warrant issue.

Reasoning

The Court asked whether the affidavit gave a judge enough reason to approve the search. Citing its Aguilar test, the majority said an informant’s tip must show either why the informant is credible or how the informant got the information. Here the tip merely named phone numbers and alleged gambling; the affidavit gave no detail about how the informant knew or why the source was reliable. The Court held that the brief FBI surveillance and phone records did not make the tip as trustworthy as a tip meeting Aguilar’s standards, so the warrant lacked probable cause and the conviction could not stand.

Real world impact

The decision restricts when judges may rely on anonymous tips to issue warrants. Police will need clearer evidence of how an informant learned key facts or stronger independent corroboration before getting search warrants; evidence gathered under similar thin affidavits may be suppressed.

Dissents or concurrances

Several Justices disagreed: Justice White concurred but urged a broader reading of earlier cases; Justices Black, Fortas, and Stewart dissented, arguing the affidavit was adequate and warning the ruling hampers law enforcement.