The Board, in the exercise and performance of its functions, duties, and powers under the provisions of this title, is authorized to hold and conduct hearings, issue subpoenas requiring the attendance of witnesses and the production of records, memoranda, papers, and other documents, administer oaths, and take testimony thereunder. When a review is ordered by the Board concerning any correctional facility subject to the Board’s jurisdiction or concerning the conduct of persons connected therewith, the chairman of the Board, by order of the Board, may issue a summons directed to the sheriff of the county or city in which such institution is located commanding him to summon any person to be present on a certain day at such place within such county or city as may be designated by the Board to give evidence before the Board. The Board shall have like powers to issue a summons directed to the sheriff and to direct the sheriff to enforce such summons. The chairman of the Board shall make the entry required of the clerk by § 17.1-612 concerning the amount any witness is to be paid as if the attendance of the witness was before a court. The sum to which the witness is entitled shall be paid out of the funds appropriated to the Board.