From the Missouri Revised Statutes -- Chapter 214, Cemeteries, Section 214.131 (passed into law in 1987).
Tombstones, fences, destroying or mutilating in abandoned family or private cemetery, penalty--abandoned or private burying ground, is defined as
214. 131. Every person who shall knowingly destroy, mutilate, disfigure, deface, injure or remove any tomb, monument or gravestone, or other structure placed in any abandoned family cemetery or private burying ground, or any fence, railing, or other work for the protection or ornamentation of any such cemetery or place of burial of any human being, or tomb, monument, or gravestone, memento, or memorial, or other structure aforesaid, or of any lot within such cemetery is guilty of a class A misdemeanor. For the purposes of this section and subsection I of section 214.132, an "abandoned family cemetery" or "private burying ground" shall include those cemeteries or burying grounds which have not been deeded to the public as provided in chapter 214, and in which no body has been interred for at least twenty-five years.
Source: "History Spotlight: MoSGA Fights to Protect Abandoned Cemeteries." By Martha Henderson, MoSGA Historical Director. Show Me State Genealogical News, Columbia, MO, Spring 2014. Vol. 35, No. 1.