; (2) the term documentary material includes the original or any copy of any book, record, report, memorandum, paper, communication, tabulation, chart, or other document, or data compilations stored in or accessible through computer or other information retrieval systems, together with instructions and all other materials necessary to use or interpret such data compilations, and any product of discovery; (3) the term investigation means any inquiry conducted for the purpose of ascertaining whether any person is or has been engaged in any violation of this Act; (4) the term investigator means any attorney or investigator employed by the Department of Justice who is charged with the duty of enforcing or carrying into effect this Act, or any officer or employee of the United States acting under the direction and supervision of such attorney or investigator in connection with an investigation; (5) the term official use means any use that is consistent with the law, and the regulations and policies of the Department of Justice, including use in connection with internal Department of Justice memoranda and reports; communications between the Department of Justice and a Federal, State, or local government agency, or a contractor of a Federal, State, or local government agency, undertaken in furtherance of a Department of Justice investigation or prosecution of a case; oral examinations; depositions; preparation for and response to civil discovery requests; introduction into the record of a case or proceeding; applications, motions, memoranda and briefs submitted to a court or other tribunal; and communications with Government investigators, auditors, consultants and experts, the counsel of other parties, arbitrators and mediators, concerning an investigation, case or proceeding