8 (iii) the most expeditious or advantageous method of enforcing or preserving any claim referred to in subparagraph (i); (b) and to report to the Minister on the result of his investigation; and (c) to exercise any other function conferred upon him by or in terms of this Act. (2) In the exercise of his functions, an investigator shall have power— (a) to call for the production of, and examine, take extracts from and, for the duration of his investigation, take possession of any books or records belonging to or in the custody of the specified person concerned or any other person employed by or in any way associated with the specified person; (b) to examine any property of the specified person concerned; (c) in addition to his powers in terms of section nine, to question the specified person concerned or any other person employed by or in any way associated with the specified person; (d) to enter and search any premises— (i) belonging to or controlled by the specified person concerned; or (ii) wherein or whereon he has reason to believe there may be evidence as to any transaction carried out by or on behalf of the specified person concerned: Provided that an investigator shall not enter or search any premises in terms of this paragraph without the consent of the occupier unless there are reasonable grounds for believing that the entry is necessary for the prevention, investigation or detection of an offence. (3) An investigator appointed in terms of section seven may exercise his functions in terms of this Act through any employee, assistant or other person authorized by him. 9 Examination of persons by investigators (1) If at any time an investigator considers it necessary or desirable to do so, he may summon— (a) the specified person to whom he has been assigned; or (b) any other person, including the spouse of the specified person, who, in the opinion of the investigator— (i) may be able to give material information concerning the affairs or property of the specified person or concerning any transaction carried out by him or on his behalf; or (ii) has in his possession or custody any book, document or record containing any information referred to in subparagraph (i); to appear before the investigator for examination at a place, time and date specified in the summons and, where appropriate, to bring with him any book, document or record specified in the summons. (2) A summons in terms of subsection (1) shall be in writing and may be served upon the person to whom it is addressed by the investigator or a police officer or by any person authorized by the investigator.