Section 835.10 - Testimony in Federal, State, or local criminal investigations and other proceedings(a) As with civil litigation, the Board prefers that testimony be taken by deposition if court rules permit, and that testimony await the issuance of the factual accident report. The Board recognizes, however, that in the case of coroner's inquests and grand jury proceedings this may not be possible. The Board encourages those seeking testimony of Board employees to contact the General Counsel as soon as such testimony is being considered. Whenever the intent to seek such testimony is communicated to the employee, he shall immediately notify the General Counsel.(b) In any case, Board employees are prohibited from testifying in any civil, criminal, or other matter, either in person or by deposition or interrogatories, absent advance approval of the General Counsel. The Board discourages the serving of a subpoena for testimony but, if issued, it should be served on the General Counsel, rather than the employee.(c) If permission to testify by deposition or in person is granted, testimony shall be limited as set forth in § 835.3 . Only factual testimony is authorized; no expert or opinion testimony shall be given.63 FR 71608, Dec. 29, 1998