Rene Martin Verdugo-Urquidez (defendant), a Mexican citizen and resident, was arrested by United States (plaintiff) law enforcement and charged with narcotics offenses. After the arrest, a federal agent received authorization from Mexican authorities to search two homes of Verdugo-Urquidez in Mexico. No warrant was procured. Verdugo-Urquidez sought to suppress evidence that was seized in the search. A federal district judge granted his motion on the ground that the search and seizure violated the Fourth Amendment. The Court of Appeals for the Ninth Circuit affirmed. The United States petitioned the Supreme Court for certiorari.