4. When a complaint is lodged against an officer alleging the commission by him of any misconduct referred to in the Schedule, the following procedure shall be adopted:
(a)
the complaint shall be communicated in writing to the officer who may be required to submit a written explanation within 24 hours or such further time as the Permanent Secretary may allow; and
(b)
where the Permanent Secretary is of the opinion that the complaint requires further investigation, he shall appoint to conduct the investigation a public officer —
(i)
of not less than Division II rank; and
(ii)
of a rank or grade senior to that of the officer under investigation.