18 U.S.C. § 3109
Verified against govinfo.gov as of June 20, 2026View official text on govinfo.gov ↗
The officer may break open any outer or inner door or window of a house, or any part of a house, or anything therein, to execute a search warrant, if, after notice of his authority and purpose, he is refused admittance or when necessary to liberate himself or a person aiding him in the execution of the warrant.