Mo. Rev. Stat. § 56.070: Prosecuting attorney's duties — exception.

1. The prosecuting attorney shall represent generally the county in all matters of law, investigate all claims against the county, and draw all contracts relating to the business of the county. He shall give his opinion, without fee, in matters of law in which the county is interested, and in writing when demanded, to the county commission or any judge thereof, except in counties in which there is a county counselor.

2. Notwithstanding the provisions of subsection 1, in any county of the first class not having a charter form of government for which a county counselor is appointed, the prosecuting attorney shall only perform those duties prescribed by subsection 1 which are not performed by the county counselor under the provisions of law relating to the office of county counselor.