Mo. Rev. Stat. § 544.250
No prosecuting or circuit attorney in this state shall file any information charging any person or persons with any felony, until such person or persons shall first have been accorded the right of a preliminary examination before some associate circuit judge in the county where the offense is alleged to have been committed in accordance with this chapter. And if upon such hearing the associate circuit judge shall determine that the alleged offense is one on which the accused may be released, the associate circuit judge may release him as provided in section 544.455 conditioned for his appearance at a time certain before a circuit judge, or associate circuit judge who is specially assigned, and thereafter as directed by the court to answer such charges as may be preferred against him, abide sentence and judgment therein, and not to depart the court without leave; provided, a preliminary examination shall in no case be required where same is waived by the person charged with the crime, or in any case where an information has been substituted for an indictment as authorized by section 545.300.
§ 544.250, RSMo
Effective 1/2/1979