(2) be responsible to or subject to the supervision or direction of an employee or agent engaged in the performance of investigative or prosecuting functions for an agency.
An employee or agent engaged in the performance of investigative or prosecuting functions for an agency in a case may not, in that or a factually related case, participate or advise in the decision, recommended decision, or agency review pursuant to section 557 of this title, except as witness or counsel in public proceedings. This subsection does not apply-
(A) in determining applications for initial licenses;
(B) to proceedings involving the validity or application of rates, facilities, or practices of public utilities or carriers; or
(C) to the agency or a
member or members of the body comprising the agency.