17 CFR 12.8: Separation of functions.

(a) An Administrative Judge, or Administrative Law Judge, will not be responsible to or subject to the supervision or direction of any officer, employee, or agent of the Commission engaged in the performance of investigative or prosecutorial functions for the Commission.

(b) No officer, employee, or agent of the Federal Government engaged in the performance of investigative or prosecutorial functions in connection with any proceeding shall, in that proceeding or a factually related proceeding, participate or advise in the decision of an Administrative Judge, or Administrative Law Judge, except as a witness in the proceeding, without the express written consent of the parties to the proceeding. This paragraph (b) shall not apply to the Commissioners.