The Investigating Officer(s), in connection with any Board-Initiated Investigation, may interview or depose witnesses, inspect property and facilities, and request and require the production of any information, documents, books, papers, correspondence, memoranda, agreements, or other records, in any form or media, that are likely to be directly relevant to the issues of the Board-Initiated Investigation. The Investigating Officer(s), in connection with a Board-Initiated Investigation, also may issue subpoenas, in accordance with 49 U.S.C. 1321 , to compel the attendance of witnesses, the production of any of the records and other documentary evidence listed above, and access to property and facilities.
49 C.F.R. § 1122.9