D.C. Mun. Regs. tit. 18, r. 18-1030
Hearings shall be open to the parties and to such other persons as the examiner considers necessary or proper.
If the examiner believes that there is relevant and material evidence available which has not been presented at the hearing, the examiner may adjourn the hearing, or, at any time prior to the mailing of notice of the decision, reopen the hearing for the receipt of such evidence.
The order in which evidence and allegations shall be presented and the procedure at the hearing generally, except as otherwise provided in this chapter shall be in the discretion of the examiner and of such nature as to afford the parties a reasonable opportunity for fair hearing and comport with the burden of proof.
Unless required for the disposition of ex parte matters authorized by law, examiners assigned to any proceedings under this chapter to render a decision or to make findings of fact and conclusions of law in an individual proceeding shall not communicate, directly or indirectly, in connection with any issue of fact, with any person or party, nor, in connection with any issue of law, with any party or his or her attorney except upon notice and opportunity for all parties to participate.
An examiner may communicate with members of the Department and may have the aid and advice of one or more of his or her assistants, but such communications, aid, and advice shall be noted on the record.
D.C. Mun. Regs. tit. 18, r. 18-1030