Missouri Revised Statutes Title XXXVII. Criminal Procedure § 545.660. When judge deemed incompetent to try case

(1) When the judge of the court in which said case is pending is near of kin to the defendant by blood or marriage; or

(2) When the offense charged is alleged to have been committed against the person or property of such judge, or some person near of kin to him by blood or marriage; or

(3) When the judge is in any wise interested or prejudiced, or shall have been counsel in the cause; or

(4) When the defendant shall make and file an affidavit, supported by the affidavit of at least two reputable persons, not of kin to or counsel for the defendant, that the judge of the court in which said cause is pending will not afford him a fair trial.