Mo. Rev. Stat. § 50.755: Purchasing agent to investigate need for supplies requested by officers.

All county officers, officials or employees shall make known to the county purchasing agent, if one is appointed as herein provided, any and all requirements that may exist for the purchase of any and all articles needed for the proper conduct or duties of their office or position, and it shall be the duty of such purchasing agent, under the direction of the county commission, to investigate and determine if such article or articles are necessary and actually required for the proper conduct of the official business of the county.