MO HB1599

Establishes single-stage trial procedure for first degree murder cases where death penalty is not sought or has been waived, with guilt and punishment decided together.

Requires two-stage trial for first degree murder when death penalty is not waived: first stage determines guilt only, second stage addresses punishment if defendant convicted.

Changes punishment determination criteria in subsection 4(4) from "sufficient to outweigh" to "not outweighed by" regarding mitigating evidence versus aggravating evidence.

Mandates life imprisonment without parole eligibility instead of death penalty if trier finds by preponderance that defendant is mentally retarded, or fails to find beyond reasonable doubt at least one statutory aggravating circumstance, or determines mitigating evidence is not outweighed by aggravating evidence.

Applies only to offenses committed on or after August 28, 2001.