Any person subject to this chapter who, without justification or excuse, unlawfully kills a human being, when he - (1) has a premeditated design to kill; (2) intends to kill or inflict great bodily harm; (3) is engaged in an act which is inherently dangerous to another and evinces a wanton disregard of human life; or (4) is engaged in the perpetration or attempted perpetration of burglary, sodomy, rape, robbery, or aggravated arson; is guilty of murder, and shall suffer such punishment as a court-martial may direct, except that if found guilty under clause (1) or (4), he shall suffer death or imprisonment for life as a court-martial may direct.