Any member of the board shall have power to administer oaths in any matter before the board for consideration or inquiry and to issue subpoenas requiring witnesses to appear before the board. Such subpoenas shall be signed by a member of the board and issued in the name of the state of Washington and be served and returned, and mileage and witness fees shall be paid in like manner and effect as in a civil action. A witness wilfully disobeying such subpoena served upon the witness shall be proceeded against upon complaint of the board to the attorney general or the prosecuting attorney of the county where the attendance of the witness was demanded as for a contempt of the authority of the superior court of said county.