Murder is contrary to Common law.(defined by Lord Coke in the 17th century)
The Actus Reus of murder is: The unlawful killing of a reasonable person in being, under the King'speace, within any country of realm and causing death in fact or law.
The killing needs to be unlawful.(not in self defence)
If it is a person in the scenario thats has been killed and not a unborn child then just apply straights away by sating X is a reasonableperson of being.
If it is a unborn child then state: A feotus in the womb, having noexistence independent of its mother, is not defined in law as 'inbeing'. It is only considered to be such when it has been fullyexpelled from its mother's body.
If the feotus is bornalive after the stabbing and then dies it is involuntary manslaughter as said in CP v CICA and AG's Ref No.3 of 1944.
One who is 'brain dead' is not generally considered to be a 'reasonable person in being' as said in Malcherek and steel.
The killing of an enemy in war is not murder, as such a person is not 'under the King's peace
Within any country of real means the killing has to be in a country which has a monarch.
The Mens Rea of murder is : Malice aforethought, express or implied
direct or oblique intention to kill or cause GBH (Vickers)