District of Columbia Code Division I. Government of District. § 1-301.21. Subpoena power.

(a)(1) The Mayor of the District of Columbia shall have the power to issue subpoenas to compel witnesses to appear and testify and/or to produce all books, records, papers, or documents in any investigation or examination of any municipal matter with respect to functions transferred to the Mayor by Reorganization Plan No. 3 of 1967 or by the District of Columbia Home Rule Act (Chapter 2 of this title): Provided, that witnesses other than those employed by the District of Columbia subpoenaed to appear before the Mayor shall be entitled to reasonable fees as established by regulations issued by the Mayor of the District of Columbia, but said fees need not be tendered said witnesses in advance of their appearing and testifying and/or producing books, records, papers, or documents.

(2) For the purposes of this subsection, the term “municipal matter” means personnel matters concerning police officers and firefighters of the District of Columbia.