Massachusetts statutory law does not define voluntary manslaughter. Rather, Massachusetts common law, as announced by the courts, provides a definition for manslaughter:
The unlawful killing of another, intentionally caused from a sudden transport of passion or heat of blood:
(1) upon a reasonable provocation and without malice or upon sudden combat; or
(2) from the excessive use of force in self-defense.
Voluntary manslaughter represents another form of intentional homicide; however a perpetrator of voluntary manslaughter kills without malice, which distinguishes the crime from murder. While the defendant intended to kill the victim or cause great bodily harm, because of the presence of mitigating circumstances, the law holds that malice does not exist and consequently reduces the crime from murder to voluntary manslaughter.
The law considers a killing voluntary manslaughter when it occurs out of passion or the heat of the moment that results from reasonable provocation or sudden fighting. Voluntary manslaughter law applies when the defendant's act occurs as a result of something which happened "that would have been likely to produce in an ordinary person such a state of passion, anger, fear, fright, or nervous excitement as would eclipse his capacity for reflection or restraint, and [which] actually did produce such a state of mind in the defendant." In other words, voluntary manslaughter occurs when provocation causes a defendant to lose control. The provocation that produces the passion, anger, fear, fright, or nervous excitement must also occur within a certain period of time prior to the killing. The law requires that in the time that passes between the provocation and killing, a reasonable person would not have "cooled off". In addition, the law requires that the defendant not actually "cool off" in the interval between the provocation and the deadly act.
The law determines what represents adequate provocation based on the objective standard of whether an ordinary person would have been provoked by the situation in question. Massachusetts holds that, in general, words alone do not serve as a sufficient basis for legally adequate provocation. The message conveyed by the words may, in certain, limited circumstances, supply the necessary provocation to prompt the heat of passion or loss of control required. A light blow, a non-threatening physical gesture, or trespass to real estate are not sufficient provocation. In cases concerning adultery or infidelity, the suspicion that one's spouse is committing adultery does not represent a sufficient provocation, though observing one's spouse in the act of adultery or hearing such acts may constitute legally sufficient provocation. Finally, a defendant's voluntary intoxication does not constitute a provocation sufficient to lessen the degree of the crime to voluntary manslaughter.
In addition to provocation, a loss of control that negates malice may also occur as a result of sudden combat or fighting. Massachusetts law considers a killing that occurs under circumstances of sudden combat as not deliberate. Instead, Massachusetts courts have found that such killings result from chance and the frailty of humanity, and are therefore not malicious and not murder. It is for these reasons that the law categorizes such killings as voluntary manslaughter.
Finally, while people may use force to defend themselves from imminent harm, if they use excessive force that results in the death of their attacker, they have committed voluntary manslaughter.
The maximum sentence for a voluntary manslaughter conviction is imprisonment for twenty years, except in circumstances where the voluntary manslaughter involves explosives or infernal machines, in which cases the maximum punishment is life imprisonment.