The procedures and fees provided for in this article shall not apply to public records, including records that are exempt from disclosure pursuant to Code Section 50-18-72, which are requested in writing by a state or federal grand jury, taxing authority, law enforcement agency, or prosecuting attorney in conjunction with an ongoing administrative, criminal, or tax investigation. The lawful custodian shall provide copies of such records to the requesting agency unless such records are privileged or disclosure to such agencies is specifically restricted by law.