Mo. Rev. Stat. § 544.180
Current with changes from the 2023 Legislative Session
An arrest is made by an actual restraint of the person of the defendant, or by his submission to the custody of the officer, under authority of a warrant or otherwise. The officer must inform the defendant by what authority he acts, and must also show the warrant if required.
§ 544.180, RSMo
RSMo 1939 § 3959