45 CFR § 1603.4
How does a person request voluntary testimony from an employee?
April 14, 2021
(a) All requests for testimony by an employee in his or her official capacity, except employees of OIG described in paragraph (b) of this section, and not subject to the exceptions set forth in §1603.1(d) of this part must be in writing and addressed to the General Counsel.
(b) All requests for testimony by an employee of the OIG must be in writing and addressed to the OIG Legal Counsel.
(c) Requests must state the nature of the requested testimony, why the information sought is unavailable by any other means, and the reasons why the testimony would be in the interest of LSC.