Missouri Revised Statutes Title XXXVII. Criminal Procedure § 550.170. Costs of three witnesses allowed

The judge and prosecuting attorney shall in no case tax the state or county with more than the costs of three witnesses to establish any one fact, nor with the costs of witnesses unnecessarily summoned and not examined, but the costs of such surplus or unnecessary witnesses shall, in the discretion of the court, be taxed against the party or attorney causing them to be summoned.