Mo. Rev. Stat. § 40.234
40.234 Duty status required for conviction on certain offenses.
40.234. Duty status required for conviction on certain offenses. — No person may be tried or punished for any offense provided for in sections 40.237 to 40.415 , unless it was committed while the person was in a duty status.
(L. 1984 H.B. 1035 § 77)