D.C. Code § 5-1021

After July 1, 1902, the several provisions of subchapter I of this chapter shall be applicable to and enforceable in any investigation or examination of any municipal matter by the Mayor of the District of Columbia, and the Council of the District of Columbia with respect to functions transferred to it by Reorganization Plan No. 3 of 1967, as well as to the proceedings before the trial boards named in that subchapter; and said Mayor and each member of the Council are hereby authorized to administer oaths to witnesses summoned in any such investigation or examination aforesaid.