5(1)It shall be the duty of the Commission in the case of every complaint referred to it by a police authority or chief officer, to determine whether or not it is necessary for the complaint to be investigated.
(2)Where the Commission determines under this paragraph that it is not necessary for a complaint to be investigated, it may, if it thinks fit, refer the complaint back to the appropriate authority to be dealt with by that authority in accordance with paragraph 6.
(3)Where the Commission refers a complaint back under sub-paragraph (2), it shall give a notification of the making of the reference back—
(a)to the complainant, and
(b)except in a case where it appears to the Commission that to do so might prejudice a possible future investigation of the complaint, to the person complained against.