26 CFR 301.7604-1: -1 Enforcement of summons.

(a) In general. Whenever any person summoned under section 6420(e)(2), 6421(f)(2), or 7602 neglects or refuses to obey such summons, or to produce books, papers, records, or other data, or to give testimony, as required, application may be made to the judge of the district court or to a U.S. commissioner for the district within which the person so summoned resides or is found for an attachment against him as for a contempt.

(b) Persons who may apply for an attachment. The officers and employees of the Internal Revenue Service whom the Commissioner has designated to carry out the authority given him by § 301.7602-1(b) to issue a summons are authorized to apply for an attachment as provided in paragraph (a) of this section.