Homicide is the act of one person causing the death of another person. Not all homicides are murder—some are manslaughter due to mitigating circumstances—and some are lawful when justified by an affirmative defense such as self-defense or insanity.

Criminal homicide generally involves (1) intent to cause death or serious bodily injury, or (2) negligence that causes the death of another person. Criminal homicide committed with the intent to cause death or serious bodily injury is generally charged as the criminal offense of murder (committed with intent and with premeditation or malice) or as voluntary manslaughter or second degree murder (committed with intent but without premeditation or malice).

And criminal homicide caused by negligence is generally charged as the criminal offense of involuntary manslaughter—for example, when a person is driving recklessly or speeding and hits another motor vehicle or pedestrian, causing the death of the other motorist or the pedestrian. A person driving a motor vehicle while intoxicated by drugs or alcohol who hits another motor vehicle or pedestrian, causing the death of the other motorist or the pedestrian, may be charged with involuntary manslaughter, or with a more specific offense like intoxication manslaughter or vehicular homicide—depending on applicable state laws.

Criminal homicide laws vary from state to state—including the names, degrees of severity, and punishments. These laws are generally found in a state’s statutes—often in the penal or criminal code.

In Michigan, homicide is defined as the killing of one person by another and can be classified as either lawful or unlawful. Unlawful homicide includes murder and manslaughter, which are differentiated by the presence of intent, premeditation, and malice. Murder is typically charged when there is an intentional killing with premeditation or malice aforethought. First-degree murder involves premeditation, while second-degree murder is committed with malice but without premeditation. Voluntary manslaughter occurs when a homicide is committed intentionally but without malice or premeditation, often in the heat of passion. Involuntary manslaughter in Michigan usually involves unintentional killing resulting from negligence or recklessness, such as in cases of vehicular homicide where a person causes death while driving recklessly or under the influence of drugs or alcohol. Michigan law also recognizes the affirmative defenses of self-defense and insanity, which can justify a homicide and result in a lawful killing. The specific statutes governing homicide can be found in Michigan's penal code, and the degrees of severity and punishments for these offenses are set by state law.