Mo. Rev. Stat. § 217.275: Carrying letters or writings without authorization prohibited, penalty.

1. Only those persons designated to do so by the chief administrative officer of a correctional center shall bring into or carry out of any correctional center under the control of the department any letter, writing, or thing of value to or from any offender.

2. Anyone who violates the provisions of this section is guilty of a class A misdemeanor.