Mo. Rev. Stat. § 26.070

It shall be the duty of every public official, agent or employee of the state, and every official and employee of any county, municipality, township, school district or road district to permit such auditor or accountant to have access to the accounts, records, documents, vouchers and papers in the care or custody or under the control of any public official, or any employee of the state or any subdivision thereof upon any subject relating to the condition, management and expenses of the office, department, board, bureau, commission or institution being audited.