Mo. Rev. Stat. § 86.523

In the event of resignation or dismissal from the force, any member who has faithfully served at least five years and less than twenty-five years in the department shall receive a refund from the pension fund of all moneys he may have theretofore paid in as salary contribution, except thirty-three and one-third percent of his salary contribution the member shall have paid into the fund, except that no refund shall be made from the fund because of the death or retirement of members or when the resignation or dismissal of a member from the force was occasioned or required by the culpable misconduct of the member.