Missouri Revised Statutes Title XXXVIII. Crimes and Punishment; Peace Officers and Public Defenders § 565.004. Joinder of offenses, exception--prior offenders, procedure, exception, first degree murder--joinder, first degree murder, waiver of death penalty

1. Each homicide offense which is lawfully joined in the same indictment or information together with any homicide offense or offense other than a homicide shall be charged together with such offense in separate counts. A count charging any offense of homicide may only be charged and tried together with one or more counts of any other homicide or offense other than a homicide as provided in subsection 2 of section 545.140. Except as provided in subsections 2, 3, and 4 of this section, no murder in the first degree offense may be tried together with any offense other than murder in the first degree. In the event of a joinder of homicide offenses, all offenses charged which are supported by the evidence in the case, together with all proper lesser offenses under section 565.029, shall, when requested by one of the parties or the court, be submitted to the jury or, in a jury-waived trial, considered by the judge.

2. A count charging any offense of homicide of a particular individual may be joined in an indictment or information and tried with one or more counts charging alternatively any other homicide or offense other than a homicide committed against that individual. The state shall not be required to make an election as to the alternative count on which it will proceed. This subsection in no way limits the right to try in the conjunctive, where they are properly joined under subsection 1 of this section, either separate offenses other than murder in the first degree or separate offenses of murder in the first degree committed against different individuals.

3. When a defendant has been charged and proven before trial to be a prior offender pursuant to chapter 558 so that the judge shall assess punishment and not a jury for an offense other than murder in the first degree, that offense may be tried and submitted to the trier together with any murder in the first degree charge with which it is lawfully joined. In such case the judge will assess punishment on any offense joined with a murder in the first degree charge according to law and, when the trier is a jury, it shall be instructed upon punishment on the charge of murder in the first degree in accordance with section 565.030.

4. When the state waives the death penalty for a murder first degree offense, that offense may be tried and submitted to the trier together with any other charge with which it is lawfully joined.