Mo. Rev. Stat. § 57.201: Deputies, appointment, compensation — serve at pleasure of sheriff (certain first class counties).

1. The sheriff of all counties of the first class not having a charter form of government shall appoint such deputies, assistants and other employees as he deems necessary for the proper discharge of the duties of his office and may set their compensation within the limits of the allocations made for that purpose by the county commission. The compensation for the deputies, assistants and employees shall be paid in equal installments out of the county treasury in the same manner as other county employees are paid.

2. The assistants and employees shall hold office at the pleasure of the sheriff.

3. A deputy sheriff, as the term deputy sheriff is defined under section 57.015 shall hold office pursuant to the provisions of sections 57.015 and 57.275.