Murder is the unlawful killing of a human person with malice aforethought, as defined in Common Law countries. Murder is generally distinguished from other forms of homicide by the elements of malice aforethought and the lack of lawful justification. All jurisdictions, ancient and modern, consider it a most serious crime and therefore impose severe penalty on its commission.

 

Common law murder is defined as the unlawful killing of a human person with malice aforethought if the defendant acts with any of the following states of mind:

(i) Intent to kill; (ii) Intent to inflict serious bodily harm; (iii) Reckless indifference to an unjustifiably high risk to human life (abandoned and malignant heart); or (iv) Intent to commit a felony (felony-murder doctrine).

Under element (i) intent to kill, the deadly weapon rule applies. Thus, if the defendant intentionally uses a deadly weapon or instrument against the victim, such use authorizes a permissive inference of intent to kill. An example of a deadly weapon or instrument is a gun, a knife, or even a car when intentionally used to strike the victim.

Under element (iii) abandoned and malignant heart, the killing must result from defendant's conduct involving a reckless indifference to human life and a conscious disregard of an unreasonable risk of death or serious bodily injury. An example of this is a 2007 law in California where an individual could be convicted of second-degree murder if he or she kills another person while operating a motor vehicle while being under the influence of alcohol, drugs, or controlled substances.

Under element (iv) felony-murder doctrine, the felony committed must be an inherently dangerous felony, such as burglary, arson, rape, robbery or kidnapping. Importantly, the underlying felony cannot be a lesser-included offense such as assault, otherwise all criminal homicides would be murder as all criminal homicides are felonies.