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 New York State, homicide encompasses various degrees of severity and legal classifications, including murder, manslaughter, and justifiable homicide. Murder is typically charged when there is intent to cause death or serious bodily harm, and it is premeditated (first-degree murder) or committed with a depraved indifference to human life (second-degree murder). Manslaughter is divided into two degrees in New York: first-degree manslaughter involves intent to cause serious physical injury that results in death, or death caused under certain extreme emotional disturbances; second-degree manslaughter involves reckless behavior that leads to another's death. Involuntary manslaughter, while not specifically categorized under New York law, would generally fall under the category of criminally negligent homicide, which occurs when a person's negligence leads to the death of another, such as in some vehicular homicides. Defenses like self-defense or insanity may justify or excuse the homicide, making it lawful under specific circumstances. The exact charges and potential penalties for homicide offenses are detailed in New York's Penal Law.