Mo. Rev. Stat. § 43.190

43.190. Authority to arrest, pursue violators. — The members of the patrol, with the exception of the director of radio and radio personnel, are hereby declared to be officers of the state of Missouri and shall be so deemed and taken in all courts having jurisdiction of offenses against the laws of this state. The members of the patrol shall have the powers now or hereafter vested by law in peace officers except the serving or execution of civil process. The members of the patrol shall have authority to arrest without writ, rule, order or process any person detected by him in the act of violating any law of this state. When a member of the patrol is in pursuit of a violator or suspected violator and is unable to arrest such violator or suspected violator within the limits of the district or territory over which the jurisdiction of such member of the patrol extends, he shall be and is hereby authorized to continue in pursuit of such violator or suspected violator into whatever part of this state may be reasonably necessary to effect the apprehension and arrest of the same and to arrest such violator or suspected violator wherever he may be overtaken.

(RSMo 1939 § 8359, A.L. 1949 p. 293) (1953) Highway patrolman, being an officer of the state, has the right to arrest without warrant a person whom he has probable cause to believe guilty of felony. State v. Campbell (Mo.), 262 S.W.2d 5.