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Missouri Criminal Law - Process, Issues, and Research: Primary Sources

Last updated by Tyler Kraft, JD '24


Criminal law is itself derived entirely from statute. Constitutions are relevant for the purposes of interpretation and setting limits on the power of statutes to penalize conduct. Case law provides the necessary interpretations of the statutes and their elements, so as to enable to the attorney to understand precisely what each element means. The vast majority of the work done in criminal law involves research using these sources. However, this guide will not spend time discussing these sources, because law school spends a great deal of time teaching students how to access and use these resources.

Instead, this guide will discuss two very important primary sources that assist the attorney in navigating the criminal justice system and understand the burdens placed on the state to prove their case.

The Revised Statutes of Missouri may be accessed for free.

  • Chapters 540-552 cover Criminal Procedure.
  • Chapters 556-600 cover Crimes and Punishment, Peace Officers, and Public Defenders.

The Missouri Constitution may be accessed for free.

Missouri Supreme Court Rules

The Missouri Supreme Court Rules establish the procedures to be followed as a case goes through the criminal justice system. Rules 19-36 govern Criminal Procedure in Missouri. Most of the rules are straightforward in nature. For example, Rule 22.01 simply states that “[f]elony proceedings may be initiated by complaint or by indictment.” Rule 22.02 indicates the form the complaint must take, and 23.01 indicates the form the indictment must take.

While the rules are procedural in nature, the failure to adhere to these procedures can have consequences for a criminal case. For example, Rule 28.02 governs the use of jury instructions and jury forms in criminal cases. 28.02(f) indicates that the failure to adhere to Rule 28.02 on jury instructions “shall constitute error, the error’s prejudicial effect to be judicially determined.” Case law on this matter shows that this error is presumptively prejudicial, so long as the defense offered a timely objection to the violative jury instruction. (State v. Galbreath, 244 S.W.3d 239, 246 (Mo. App. S.D. 2008).

Thus, it is important to consider the effects of Missouri’s Rules of Criminal Procedure, and ensure that one adheres to them during the course of the proceeding.

Missouri Approved Instructions - Criminal

Known as the MAI-CR, these are the jury instructions utilized in criminal proceedings in Missouri. Missouri Supreme Court Rule 28.02 requires the MAI-CR instruction to be given to the exclusion of any other instruction, so long as the MAI-CR instruction is applicable.

This source is useful for two reasons. First, from the standpoint of criminal practice, it is necessary to consult it when drafting proposed jury instructions, because the instructions contained in the MAI-CR will heavily dictate how the jury is instructed. Second, and more notable for this guide’s purpose, the jury instructions play a key role in understanding the case.

Jury instructions inform the reader of precisely what the State must prove in order to obtain a conviction. After looking at a statute, the corresponding jury instruction in the MAI-CR is often the next thing that should be consulted. This allows the attorney to better understand how the statute is applied to fact situations, and it also allows the attorney to understand how the State will be required to present its case, and it allows the defense to begin tailoring its case to rebut the State’s position.


Accessing the MAI-CR:

For Public Defenders and prosecutors, accessing the MAI-CR is a simple process, because a searchable database is provided as part of the attorney’s computer workstation software.

Unfortunately for private attorneys, the MAI-CR is not accessible online through traditional means. The MAI-CR can only be accessed online through the Missouri Supreme Court’s publications website, and it requires a separate subscription of $250 per year.

However, the MAI-CR is available in book form, and it may be accessed for free in any courthouse in Missouri through that courthouse’s law library.