D.C. Mun. Regs. tit. 3, r. 3-407
Evidence shall be taken in conformity with D.C. Code § 2-509(b) (2006 Repl.).
The Board may permit rebuttal evidence.
Any party objecting to the admissibility of evidence shall state the grounds of the objection(s) relied upon.
Any offer of proof made in connection with an objection taken to any ruling of the Board which rejects or excludes proffered oral testimony shall consist of a statement for the record of the substance of the evidence which the person contends would be adduced by the testimony.
If excluded evidence consists of documentary evidence, a copy of the evidence shall be marked for identification and shall constitute the offer of proof.
The Board, in its discretion, may permit the withdrawal of original documents offered and received in evidence and substitute certified copies in place of the originals.
When relevant and material matters offered in evidence are embraced in a book, paper or document containing other matters, not material or relevant, the persons offering the same shall plainly designate the matter so offered, and the immaterial or irrelevant parts shall be excluded and shall be segregated insofar as practicable.
No document or other writing shall be accepted for the record after the close of the hearing, except with the consent of the Board after due notice to the opposing parties and only when the receipt of the document will not unfairly affect the interest of a party.
In a contested case conducted under § 423, witnesses may be examined or cross-examined by the Board, the complainant, respondent, or any party so determined by the Board pursuant to this chapter.
In a rulemaking case conducted under § 422, witnesses may be examined only by the Board.
D.C. Mun. Regs. tit. 3, r. 3-407