1. A person is guilty of murder, a class AA felony, if the person:
a. Intentionally or knowingly causes the death of another human being;
b. Causes the death of another human being under circumstances manifesting extreme indifference to the value of human life; or
c. Acting either alone or with one or more other persons, commits or attempts to commit treason, robbery, burglary, kidnapping, felonious restraint, arson, gross sexual imposition, a felony offense against a child under section 12.1-20-03, 12.1-27.2-02, 12.1-27.2-03, 12.1-27.2-04, or 14-09-22, or escape and, in the course of and in furtherance of such crime or of immediate flight therefrom, the person or any other participant in the crime causes the death of any person. In any prosecution under this subsection in which the defendant was not the only participant in the underlying crime, it is an affirmative defense that the defendant: (1) Did not commit the homicidal act or in any way solicit, command, induce, procure, counsel, or aid the commission thereof;
(2) Was not armed with a firearm, destructive device, dangerous weapon, or other weapon which under the circumstances indicated a readiness to inflict serious bodily injury;
(3) Reasonably believed that no other participant was armed with such a weapon; and
(4) Reasonably believed that no other participant intended to engage in conduct likely to result in death or serious bodily injury.
Subdivisions a and b are inapplicable in the circumstances covered by subsection 2.
2. A person is guilty of murder, a class A felony, if the person causes the death of another human being under circumstances which would be class AA felony murder, except that the person causes the death under the influence of extreme emotional disturbance for which there is reasonable excuse. The reasonableness of the excuse must be determined from the viewpoint of a person in that person's situation under the circumstances as that person believes them to be. An extreme emotional disturbance is excusable, within the meaning of this subsection only, if it is occasioned by substantial provocation, or a serious event, or situation for which the offender was not culpably responsible.