First-degree murder constitutes the intentional killing of a person with premeditation.
For adult offenders, it is punished by either the death penalty or life imprisonment without the possibility of parole unless the sentence is commuted by a governor.
For juvenile offenders, it is punished by life-with-parole or a prison term between 30 and 40 years.
The death penalty is possible for adults convicted of first-degree murder when the jury unanimously finds that any potential aggravating factors listed in Missouri law outweigh any potential mitigating circumstances listed in Missouri law.
(aggravating circumstances) or life imprisonment without the possibility of parole For juveniles: In the 2013 case of State v. Nathan,[4] the state supreme court remanded a mandatory sentence for a juvenile charged with first degree murder.