Unlawful homicide basically falls into two major categories murder and manslaughter Murder is the killing of a human being with malice aforethought.Malice aforethought,in turn,means an intention to kill or do,grevious bodily harm.Either of these two generic intents,if established,is sufficient to satisfy the general requirement of men rea.For example,A intends to kill B and he shoots B to death.In this case,we can say that A has committed a murder.