Mo. Rev. Stat. § 575.210: Escape or attempted escape from confinement — penalties.

1. A person commits the offense of escape or attempted escape from confinement if, while being held in confinement after arrest for any offense, while serving a sentence after conviction for any offense, or while at an institutional treatment center operated by the department of corrections as a condition of probation or parole, he or she escapes or attempts to escape from confinement.

2. The offense of escape or attempted escape from confinement in the department of corrections is a class B felony.

3. The offense of escape or attempted escape from confinement in a county or private jail or city or county correctional facility is a class E felony unless:

(1) The offense is facilitated by striking or beating any person, in which case it is a class D felony;

(2) The offense is committed by means of a deadly weapon or dangerous instrument or by holding any person as hostage, in which case it is a class A felony.