15 U.S.C. § 49

For the purposes of this subchapter the Commission, or its duly authorized agent or agents, shall at all reasonable times have access to, for the purpose of examination, and the right to copy any documentary evidence of any person, partnership, or corporation being investigated or proceeded against; and the Commission shall have power to require by subpoena the attendance and testimony of witnesses and the production of all such documentary evidence relating to any matter under investigation. Any member of the Commission may sign subpoenas, and members and examiners of the Commission may administer oaths and affirmations, examine witnesses, and receive evidence. Such attendance of witnesses, and the production of such documentary evidence, may be required from any place in the United States, at any designated place of hearing. And in case of disobedience to a subpoena the Commission may invoke the aid of any court of the United States in requiring the attendance and testimony of witnesses and the production of documentary evidence. Any of the district courts of the United States within the jurisdiction of which such inquiry is carried on may, in case of contumacy or refusal to obey a subpoena issued to any person, partnership, or corporation issue an order requiring such person, partnership, or corporation to appear before the Commission, or to produce documentary evidence if so ordered, or to give evidence touching the matter in question; and any failure to obey such order of the court may be punished by such court as a contempt thereof. Upon the application of the Attorney General of the United States, at the request of the Commission, the district courts of the United States shall have jurisdiction to issue writs of mandamus commanding any person, partnership, or corporation to comply with the provisions of this subchapter or any order of the Commission made in pursuance thereof. The Commission may order testimony to be taken by deposition in any proceeding or investigation pending under this subchapter at any stage of such proceeding or investigation. Such depositions may be taken before any person designated by the commission and having power to administer oaths. Such testimony shall be reduced to writing by the person taking the deposition, or under his direction, and shall then be subscribed by the deponent. Any person may be compelled to appear and depose and to produce documentary evidence in the same manner as witnesses may be compelled to appear and testify and produce documentary evidence before the Commission as hereinbefore provided. Witnesses summoned before the Commission shall be paid the same fees and mileage that are paid witnesses in the courts of the United States and witnesses whose depositions are taken and the persons taking the same shall severally be entitled to the same fees as are paid for like services in the courts of the United States.