(a) The investigating official, the reviewing official, and any employee or agent of the authority who takes part in investigating, preparing, or presenting a particular case may not, in such case or a factually related case:
(1) Participate in the hearing as the ALJ;
(2) Participate or advise in the review of the initial decision by the authority head; or
(3) Make the collection of penalties and assessment.
(b) The ALJ must not be responsible to or subject to the supervision or direction of the investigating official or the reviewing official.