Mo. Rev. Stat. § 479.110
479.110 Arrest without warrants, procedure.
479.110. Arrest without warrants, procedure. — The city marshal, chief of police or other police officer of any municipality shall, without a warrant, make arrests of any person who commits an offense in his presence, but such officer shall, before the trial, file a written complaint with the judge hearing violations of municipal ordinances.
(L. 1978 H.B. 1634) Effective 1-02-79