In the state of Tennessee, the statute (39-13-202) is as follows:
(a) First degree murder is:
(1) A premeditated and intentional killing of another;
(2) A killing of another committed in the perpetration of or attempt to perpetrate any first degree murder, act of terrorism, arson, rape, robbery, burglary, theft, kidnapping, aggravated child abuse, aggravated child neglect, rape of a child, aggravated rape of a child or aircraft piracy; or
(3) A killing of another committed as the result of the unlawful throwing, placing or discharging of a destructive device or bomb.
(b) No culpable mental state is required for conviction under subdivision (a)(2) or (a)(3), except the intent to commit the enumerated offenses or acts in those subdivisions.
(c) A person convicted of first degree murder shall be punished by:
(2) Imprisonment for life without possibility of parole; or
(3) Imprisonment for life.
(d) As used in subdivision (a)(1), “premeditation” is an act done after the exercise of reflection and judgment. “Premeditation” means that the intent to kill must have been formed prior to the act itself. It is not necessary that the purpose to kill pre-exist in the mind of the accused for any definite period of time. The mental state of the accused at the time the accused allegedly decided to kill must be carefully considered in order to determine whether the accused was sufficiently free from excitement and passion as to be capable of premeditation.
The Missouri statute (565.020), which does not apply to persons under 16 years of age, reads:
1. A person commits the crime of murder in the first degree if he knowingly causes the death of another person after deliberation upon the matter.
2. Murder in the first degree is a class A felony, and the punishment shall be either death or imprisonment for life without eligibility for probation or parole, or release except by act of the governor; except that, if a person has not reached his sixteenth birthday at the time of the commission of the crime, the punishment shall be imprisonment for life without eligibility for probation or parole, or release except by act of the governor.