Section 10. For the purpose of discovering violations of this chapter or a rule or regulation promulgated hereunder, or for securing information lawfully required by him, the commissioner may, at any time, and as often as he may determine, either personally or by a person designated by him, investigate the business and examine the books, accounts, records and files used therein of a licensee. The total charge for such examination, which shall be paid by the licensee within thirty days after receipt of an invoice therefor, shall be determined annually by the commissioner of administration under the provisions of section three B of chapter seven for each person participating in such examination. For such purpose, the commissioner and his duly designated representative shall have access to the offices and places of business, books, accounts, papers, records, files, safes and vaults of all such licensees. The commissioner and any person designated by him may require the attendance of and examine under oath all persons whose testimony he may require relative to such business. Copies of reports of such examinations of a licensee shall be furnished to such licensee and shall not be exhibited to any other person, organization or agency; provided, however, that the commissioner may, upon the request of a law enforcement agency made in the course of its official duties, provide copies of such reports to any such law enforcement agency.