Mo. Rev. Stat. § 559.301

There is hereby created, in each judicial circuit of this state composed of a single county of the second class, a board of paroles, to be known as such, and consisting of the circuit judges of the circuit court of the county so composing such judicial circuit. The circuit judge of that division of the circuit court to which has been assigned, for the time being, the duty of trying criminal cases, shall be ex officio chairman, and the clerk of the circuit court shall be ex officio clerk of said board of paroles. Such board of paroles is hereby empowered and authorized to consider, grant, revoke, alter, or terminate paroles and to exercise all the powers herein granted and such other powers as may be provided by law.