D.C. Code § 5-127.01

In addition to the powers vested in them by law, the Council of the District of Columbia is hereby authorized and empowered to make and modify, and the Mayor of the District of Columbia is hereby authorized and empowered to enforce, under such penalties as the Council may deem necessary, all needful rules and regulations for the proper government, conduct, discipline, and good name of said Metropolitan Police force; and said Mayor is hereby authorized and empowered to fine, suspend with or without pay, and dismiss any officer or member of said police force for any offense against the laws of the United States or the laws and ordinances or regulations of the District of Columbia, whether before or after conviction thereof in any court or courts, and for misconduct in office, or for any breaches or violation of the rules and regulations made by the Council for the government, conduct, discipline, and good name of said police force; provided, that no person shall be removed from said police force except upon written charges preferred against him in the name of the Chief of Police of said police force to the trial board or boards hereinafter provided for and after an opportunity shall have been afforded him of being heard in his defense; but no person so removed shall be reappointed to any office in said police force; provided further, that special policemen and additional privates may be removed from office by the Mayor without cause and without trial; provided further, that charges preferred against any member of said police force to the trial board or boards hereinafter provided for may be altered or amended, in the discretion of such trial board or boards, at any time before final action by such board or boards, under such regulations as the Council may adopt, provided the accused have an opportunity to be heard thereon.