A federal postal inspector set up an undercover website in a sting operation intended to catch purchasers of child pornography. Jeffrey Grubbs (defendant) ordered a video from the website. A postal inspector applied for a search warrant. The affidavit stated that the warrant would only be executed once the package containing the video had been accepted by someone at Grubbs’s residence. Two attachments to the affidavit provided information describing Grubbs’s home and the type of evidence the inspectors anticipated finding. After the package was delivered, the inspectors executed a search of Grubbs’s home. The inspectors served the warrant on Grubbs about 30 minutes into the search. The warrant included the attachments describing Grubbs’s home and the anticipated evidence, but the affidavit describing the conditions that would trigger execution of the warrant was not attached. Grubbs was arrested and ordered to appear before a grand jury on charges of receiving child pornography. Grubbs moved to exclude the search evidence and argued that the warrant was invalid because it did not contain the affidavit describing the conditions that would trigger execution. The motion was denied, and Grubbs pled guilty but reserved the right to appeal the motion denial. The appellate court reversed Grubbs’s conviction, holding that an anticipatory warrant is invalid if the affidavit describing the conditions triggering execution is not provided to the person whose property is subject to search. The United States (plaintiff) petitioned the Supreme Court for review.