of a complaint, the investigative authority may require a fact-finding conference with the parties in order to define the issues arising from the complaint, to determine which elements of the complaint are undisputed, to resolve those issues that can be resolved, and to ascertain whether there is a basis for negotiated settlement of the complaint. At the request of the covered employee involved, the investigative authority shall ensure that the parties are separated during this conference. (C) Other forms of investigation In addition to the types of investigative activity described in subparagraphs (A) and (B), the investigative authority may carry out such other types of investigative activity with respect to a complaint as it considers appropriate, including prehearing discovery and the issuance of subpoenas in accordance with subsection (f). . (b) Conforming amendments relating to subpoena authority Section 405(f) ( 2 U.S.C. 1405(f) ) is amended— (1) in paragraph (1), by striking a hearing officer may issue subpoenas and inserting an investigative authority under subsection (e) may issue subpoenas