—(1) For the purpose of investigating any offence under section 20 or 23, the Director-General or any authorised officer may —
examine orally any person supposed to be acquainted with the facts and circumstances of the case, and to reduce to writing any statement made by the person so examined; and
require by order in writing the attendance before himself of any person who, from information given or otherwise, appears to be acquainted with the facts and circumstances concerning the case and that person shall attend as so required.
(2) The person mentioned in subsection (1)(a) shall be bound to state truly the facts and circumstances with which he is acquainted concerning the case except only that he may decline to make with regard to any fact or circumstance a statement which would have a tendency to expose him to a criminal charge or to penalty or forfeiture.
(3) A statement made under this section by any person shall be read over to him and shall, after correction, if necessary, be signed by him.