United States v. Chadwick
United States Supreme Court
433 U.S. 1 (1977)
Amtrak officials suspected that a man and woman were transporting a trunk of marijuana from California to Massachusetts and alerted the police, who met the train with a drug-sniffing dog that flagged the trunk. Chadwick (defendant) arrived to collect the trunk and was arrested, along with the two travelers, as they loaded it into his car. Police took the trunk to a federal building and searched it without a warrant about ninety minutes after the arrests. The trial court suppressed the marijuana found inside, ruling the warrantless search wasn't justified as either incident to arrest or under the automobile exception, since the trunk was secure and no exigency required an immediate search.
Whether police may search a locked trunk without a warrant when they have probable cause and lawfully seized it during an arrest, but the trunk has been in their exclusive control for over an hour before the search.