Spinelli (D) was convicted for traveling to Missouri from Illinois with the intention of gambling. D appealed, challenging the search warrant obtained by the FBI to obtain the evidence used against him at trial. The application on which the warrant was based included four main parts: 1. The FBI had tracked D for five days, during four of which he traveled from Illinois to a certain apartment house in Missouri, and on one day he was further tracked to a specific apartment in the building; 2. Two phone numbers are associated with the specific apartment; 3. The government officials stated that this person was a known bookie; and 4. A reliable informant told the FBI that D was a bookie and used the two phone numbers associated with the apartment in Missouri. At every appropriate stage in the proceedings in the lower courts, D challenged the constitutionality of the warrant which authorized the FBI search that uncovered the evidence necessary for his conviction. At a pretrial suppression hearing, it was held that D lacked standing to raise a Fourth Amendment objection. D was convicted and appealed. A unanimous panel of the Court of Appeals for the Eighth Circuit rejected that ground, a majority holding that the warrant was issued without probable cause. After an en banc rehearing, the Court of Appeals sustained the warrant and affirmed the conviction by a vote of six to two. The Supreme Court granted certiorari.