Homicide is a broad term that means the killing of a human being by another human, though the exact definition and divisions differ in different jurisdictions. In the United States, homicide may be of two categories: criminal or non-criminal. There are six types of homicide that fit these two categories. A non-criminal homicide may be a justifiable homicide, such as killing in self-defense, or excusable homicide, such as an accident. Criminal homicide may be either murder in the first or second degree, voluntary manslaughter, or involuntary manslaughter, and involuntary manslaughter may be due to recklessness, on the one hand, or something termed criminal negligence or negligent homicide, on the other hand.
By way of contrast, the Finnish Penal Code Chapter 21 distinguishes six different types of homicide. They are: manslaughter, murder, killing, infanticide, negligent homicide, and grossly negligent homicide. Abortion is listed in Chapter 22.
While to act “recklessly” in the United States means to consciously disregard concerns and take a risk that is substantial and unjustified, to act “negligently” only means that one fails to use “reasonable care”; that is, negligence is a lesser offense than recklessness. In neither the case of recklessness or the case of negligence does one find the malice or premeditation that characterizes murder.
Negligence can be active or passive and criminal or not. Passive negligence generally means failure to act or failure to follow a law that is imposed on all. Active negligence, by contrast, involves an act or failure to follow a law or perform a duty that is particular to the person or which she or he agreed to. A person who is negligent according to civil law may not meet the standard of criminal law, because a greater degree of culpability is required. Unlike ordinary negligence, criminal negligence must involve extraordinarily different behavior than a normal person would engage in.
Negligent homicide may involve unintentional killing that results from criminal negligence while performing a lawful act, often involving a motor vehicle, which may be an automobile or truck, a snowmobile, or a boat. It may also include killing that results when a misdemeanor or lesser felony is involved. State laws differ, and — for example — may treat the case of alcohol involvement in a motor vehicle related killing, as in New Hampshire, or not, as in Montana. Negligent homicide also covers cases of death resulting from gross negligence in the practice of medicine or surgery.