The board may require the attendance of witnesses and the production of books, records, and papers at any hearing or with reference to any matter which the board has authority to investigate and, for that purpose, may issue a subpoena for any witness or a subpoena duces tecum to compel the production of any books, records, or papers. The fees and mileage of witnesses must be the same as may be allowed in the court in criminal cases. Fees and mileage must be paid in the same manner as expenses of the board.