Mo. Rev. Stat. § 115.199
Deceased and incompetents removed from register, when — persons convicted ...
115.199. Deceased and incompetents removed from register, when — persons convicted and pardoned, how handled. — Each election authority shall remove from its registration records the names of voters reported dead or adjudged incapacitated and shall determine the voting qualifications of those reported convicted or pardoned.
(L. 1977 H.B. 101 § 7.350, A.L. 1999 H.B. 676)