Mo. Rev. Stat. § 544.160: Escaped prisoner may be retaken after term expires.

If any person sentenced to imprisonment in a county jail or in the penitentiary on a conviction for a criminal offense shall escape, he may be pursued, retaken and imprisoned again, notwithstanding the term for which he was sentenced to be imprisoned may have expired at the time he is retaken, and remain so imprisoned until tried for such escape, or until he be discharged by a failure to prosecute therefor.