Mo. Rev. Stat. § 58.200
When the office of sheriff shall be vacant, by death or otherwise, the coroner of the county is authorized to perform all the duties which are by law required to be performed by the sheriff, until another sheriff for such county shall be appointed and qualified and such coroner shall have notice thereof. In such case, said coroner may appoint one or more deputies, with the approbation of the judge of the circuit court, and every such appointment, with the oath of office endorsed thereon, shall be filed in the office of the clerk of the circuit court of the county. If the coroner becomes the acting sheriff and the sheriff is no longer receiving the sheriff's salary, the coroner may be paid, in addition to the coroner's salary, the difference between the salaries of sheriff and coroner so that the coroner receives the equivalent of the sheriff's salary while serving as acting sheriff.
Effective dates prior to 1940 may not be the actual effective date. See FAQ 'When do laws become effective?'
§ 58.200, RSMo
RSMo 1939 § 13145, A.L. 2022 H.B. 1606