D.C. Code § 14-103: Depositions for use in State and Territorial Courts.

When a commission is issued or notice given to take the testimony of a witness found within the District of Columbia, to be used in an action pending in a court of a State, territory, commonwealth, possession, or place under the jurisdiction of the United States, the testimony may be taken by leave of a judge of the United States District Court in like manner and with like effect as other depositions are taken in United States district courts, or by leave of a judge of the Superior Court of the District of Columbia in the manner prescribed by the rules of that court.