Mo. Rev. Stat. § 544.220: Conveyance of prisoner through another county.

Every officer or other person, who shall have arrested or have in his custody, under the authority of the law of this state, any prisoner who is to be conveyed from one county to another, may carry such prisoner through such parts of any county as shall be in the ordinary route of travel from the place where such prisoner shall have been arrested to the place where he is to be conveyed and delivered, under the process or authority by which such prisoner shall have been arrested or is detained.