26 U.S.C. § 6021

Whenever there are in any internal revenue district any articles subject to tax, which are not owned or possessed by or under the care or control of any person within such district, and of which no list has been transmitted to the Secretary, as required by law or by regulations prescribed pursuant to law, the Secretary shall enter the premises where such articles are situated, shall make such inspection of the articles as may be necessary and make lists of the same, according to the forms prescribed. Such lists, being subscribed by the Secretary, shall be sufficient lists of such articles for all purposes.