A person appointed as the investigating officer in relation to a case shall undertake such inquiries as the Commission may from time to time reasonably direct him to undertake in relation to the case.

A person appointed as an investigating officer shall be permitted to act as such by the person who is the appropriate person in relation to the public body in which he is serving.

Where the chief officer of an England and Wales police force appoints a member of the Royal Ulster Constabulary as an investigating officer, the member appointed shall have in England and Wales the same powers and privileges as a member of the police force has there as a constable; and where the Chief Constable of the Royal Ulster Constabulary appoints a member of an England and Wales police force as an investigating officer, the member appointed shall have in Northern Ireland the same powers and privileges as a member of the Royal Ulster Constabulary has there as a constable.

The Commission may take any steps which they consider appropriate for supervising the undertaking of inquiries by an investigating officer.

The Commission may at any time direct that a person appointed as the investigating officer in relation to a case shall cease to act as such; but the making of such a direction shall not prevent the Commission from imposing a requirement under section 19 to appoint another investigating officer in relation to the case.

When a person appointed as the investigating officer in relation to a case submits to the Commission a report of his findings he shall also submit to them any statements, opinions and reports received by him in connection with the inquiries which he was directed to undertake in relation to the case.