TITLE 38 - US CODE - SUBCHAPTER II - INVESTIGATIONS

38 USC 5711 - Authority to issue subpoenas

(a) For the purposes of the laws administered by the Secretary, the Secretary, and those employees to whom the Secretary may delegate such authority, to the extent of the authority so delegated, shall have the power to
(1) issue subpoenas for and compel the attendance of witnesses within a radius of 100 miles from the place of hearing;
(2) require the production of books, papers, documents, and other evidence;
(3) take affidavits and administer oaths and affirmations;
(4) aid claimants in the preparation and presentation of claims; and
(5) make investigations and examine witnesses upon any matter within the jurisdiction of the Department.
(b) Any person required by such subpoena to attend as a witness shall be allowed and paid the same fees and mileage as are paid witnesses in the district courts of the United States.

38 USC 5712 - Validity of affidavits

Any such oath, affirmation, affidavit, or examination, when certified under the hand of any such employee by whom it was administered or taken and authenticated by the seal of the Department, may be offered or used in any court of the United States and without further proof of the identity or authority of such employee shall have like force and effect as if administered or taken before a clerk of such court.

38 USC 5713 - Disobedience to subpoena

In case of disobedience to any such subpoena, the aid of any district court of the United States may be invoked in requiring the attendance and testimony of witnesses and the production of documentary evidence, and such court within the jurisdiction of which the inquiry is carried on may, in case of contumacy or refusal to obey a subpoena issued to any officer, agent, or employee of any corporation or to any other person, issue an order requiring such corporation or other person to appear 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.