7 U.S.C. § 4816: Investigations

for the effective administration of this chapter; or to determine whether a person subject to this chapter has engaged, or is about to engage, in an act that constitutes, or will constitute, a violation of this chapter or an order, rule, or regulation issued under this chapter. For the purpose of such investigation, the Secretary may administer oaths and affirmations, subpoena witnesses, compel their attendance, take evidence, and require the production of any records that are relevant to the inquiry. Such attendance of witnesses and the production of such records may be required from any place in the United States. In the case of contumacy, or refusal to obey a subpoena, by a person, the Secretary may invoke the aid of a court of the United States with jurisdiction over such investigation or proceeding, or where such person resides or does business, in requiring the attendance and testimony of such person and the production of such records. The court may issue an order requiring such person to appear before the Secretary to produce records or to give testimony touching the matter under investigation. A failure to obey an order issued under this section by the court may be punished by the court as a contempt thereof. Process in such case may be served in the judicial district in which such person is an inhabitant or wherever such person may be found.