((a)) The testimony of any witness in a foreign country may be taken either on oral or written interrogatories, or on interrogatories partly oral and partly written, pursuant to a commission issued, as hereinafter provided, for the purpose of determining whether any foreign documents sought to be used in any criminal action or proceeding in any court of the United States are genuine, and whether the authentication requirements of the Federal Rules of Evidence are satisfied with respect to any such document (or the original thereof in case such document is a copy). Application for the issuance of a commission for such purpose may be made to the court in which such action or proceeding is pending by the United States or any other party thereto, after five days’ notice in writing by the applicant party, or his attorney, to the opposite party, or his attorney of record, which notice shall state the names and addresses of witnesses whose testimony is to be taken and the time when it is desired to take such testimony. In granting such application the court shall issue a commission for the purpose of taking the testimony sought by the applicant addressed to any consular officer of the United States conveniently located for the purpose. In cases of testimony taken on oral or partly oral interrogatories, the court shall make provisions in the commission for the selection as hereinafter provided of foreign counsel to represent each party (except the United States) to the criminal action or proceeding in which the foreign documents in question are to be used, unless such party has, prior to the issuance of the commission, notified the court that he does not desire the selection of foreign counsel to represent him at the time of taking of such testimony. In cases of testimony taken on written interrogatories, such provision shall be made only upon the request of any such party prior to the issuance of such commission. Selection of foreign counsel shall be made by the party whom such foreign counsel is to represent within ten days prior to the taking of testimony or by the court from which the commission issued, upon the request of such party made within such time.

((b)) Any consular officer to whom a commission is addressed to take testimony, who is interested in the outcome of the criminal action or proceeding in which the foreign documents in question are to be used or has participated in the prosecution of such action or proceeding, whether by investigations, preparation of evidence, or otherwise, may be disqualified on his own motion or on that of the United States or any other party to such criminal action or proceeding made to the court from which the commission issued at any time prior to the execution thereof. If after notice and hearing, the court grants the motion, it shall instruct the consular officer thus disqualified to send the commission to any other consular officer of the United States named by the court, and such other officer shall execute the commission according to its terms and shall for all purposes be deemed the officer to whom the commission is addressed.

((c)) The provisions of this section and sections 3493–3496 of this title applicable to consular officers shall be applicable to diplomatic officers pursuant to such regulations as may be prescribed by the President. For purposes of this section and sections 3493 through 3496 of this title, the term “consular officers” includes any United States citizen who is designated to perform notarial functions pursuant to section 1750 of the Revised Statutes, as amended ().