Mo. Rev. Stat. § 86.1130: Membership, terminated when.

Each person who becomes a member of the police retirement system under the provisions of sections 86.900 to 86.1280 shall remain a member until the earliest to occur of the following events:

(1) The termination of service of such person and the payment to such person of all benefits due such person under the provisions of sections 86.900 to 86.1280; or

(2) The death of such person.