Modifies provisions relating to trial procedures for murder in the first degree

This bill modifies the trial procedures for first-degree murder cases in Missouri, specifically outlining how trials proceed when the death penalty is not waived. Under the new rules, these trials would occur in two distinct stages: the first determines guilt or innocence, while the second stage focuses solely on sentencing if the defendant is found guilty. During the sentencing phase, the jury or judge considers evidence regarding aggravating and mitigating circumstances to decide between the death penalty and life imprisonment without parole. The legislation also clarifies the definition of intellectual disability and allows for this issue to be addressed before the trial begins under certain conditions. These procedural changes apply only to offenses committed on or after August 28, 2001.