28 United States Code §1783 and §1784
Service Abroad of U.S. Subpoenas upon U.S. Nationals or Residents
§ 1783. Subpoena of person in foreign country
(a) A court of the United States may order the issuance of a subpoena requiring the
appearance as a witness before it, or before a person or body designated by it, of a national
or resident of the United States who is in a foreign country, or requiring the production of a
specified document or other thing by him, if the court finds that particular testimony or the
production of the document or other thing by him is necessary in the interest of justice, and,
in other than a criminal action or proceeding, if the court finds, in addition, that it is not
possible to obtain his testimony in admissible form without his personal appearance or to
obtain the production of the document or other thing in any other manner.

(b) The subpoena shall designate the time and place for the appearance or for the
production of the document or other thing. Service of the subpoena and any order to show
cause, rule, judgment, or decree authorized by this section or by section 1784 of this title
shall be effected in accordance with the provisions of the Federal Rules of Civil Procedure
relating to service of process on a person in a foreign country. The person serving the
subpoena shall tender to the person to whom the subpoena is addressed his estimated
necessary travel and attendance expenses, the amount of which shall be determined by the
court and stated in the order directing the issuance of the subpoena.
§ 1784. Contempt
(a) The court of the United States which has issued a subpoena served in a foreign country
may order the person who has failed to appear or who has failed to produce a document or
other thing as directed therein to show cause before it at a designated time why he should
not be punished for contempt.

(b) The court, in the order to show cause, may direct that any of the person’s property
within the United States be levied upon or seized, in the manner provided by law or court
rules governing levy or seizure under execution, and held to satisfy any judgment that may
be rendered against him pursuant to subsection (d) of this section if adequate security, in
such amount as the court may direct in the order, be given for any damage that he might
suffer should he not be found in contempt. Security under this subsection may not be
required of the United States.

(c) A copy of the order to show cause shall be served on the person in accordance with
section  1783 (b) of this title.

(d) On the return day of the order to show cause or any later day to which the hearing may
be continued, proof shall be taken. If the person is found in contempt, the court,
notwithstanding any limitation upon its power generally to punish for contempt, may fine him
not more than $100,000 and direct that the fine and costs of the proceedings be satisfied
by a sale of the property levied upon or seized, conducted upon the notice required and in
the manner provided for sales upon execution.
28 U.S.C. 1783 and 1784, Process Service Abroad of U.S. Subpoenas upon U.S. Nationals or Residents