The board may refer any question of fact arising under any petition, including a petition for commutation heard by it, to a referee to hear evidence and report to the board the testimony taken before him or such testimony and findings of facts thereon as the board may order. The board may refer any question of fact arising out of any petition assigned to a referee, to any other referee to hear evidence and report the testimony so taken thereon to the original referee.
77 P.S. § 1519