46 C.F.R. § 4.07-35 – Counsel for witnesses and parties in interest.

(a) All parties in interest shall be allowed to be represented by counsel, to examine and cross-examine witnesses and to call witnesses in their own behalf.
(b) Witnesses who are not parties in interest may be assisted by counsel for the purpose of advising such witnesses concerning their rights; however, such counsel will not be permitted to examine or cross-examine other witnesses or otherwise participate in the investigation.