Federal agents executed a search warrant at Calandra's (D) place of business and seized alleged loan sharking records bearing the name of Dr. Loveland. D was subpoenaed before a federal grand jury, and the government petitioned to give D transactional immunity. D filed a petition to suppress, and the district court found the search warrant without probable cause and that the seizure exceeded the scope of the warrant. The Appeals court affirmed. The Supreme Court granted certiorari.