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 Wisconsin, homicide is legally defined as the act of one person causing the death of another. Not all homicides are considered murder; some may be classified as manslaughter, which includes deaths resulting from mitigating circumstances, or they may be justified by affirmative defenses such as self-defense or insanity. Wisconsin law distinguishes between different types of criminal homicide based on the perpetrator's intent and level of negligence. First-degree intentional homicide, which requires intent and premeditation, is the most severe form of murder under Wisconsin law (WI Stat § 940.01). Second-degree intentional homicide, which involves intent but lacks premeditation or is committed under mitigating circumstances, is less severe (WI Stat § 940.02). Homicide resulting from reckless behavior or negligence, such as vehicular homicide, is typically charged as reckless homicide (WI Stat § 940.06) or homicide by negligent operation of a vehicle (WI Stat § 940.10). When a death occurs due to intoxicated use of a vehicle, the charge may be homicide by intoxicated use of a vehicle (WI Stat § 940.09). The specific charges and penalties for homicide offenses in Wisconsin are detailed in the state's statutes, particularly within the penal or criminal code.