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 Washington State, homicide encompasses various degrees of severity and potential defenses. Homicide is not always considered murder; it can be classified as manslaughter or be justified under certain defenses like self-defense or insanity. Murder, which involves premeditation and intent to kill or cause serious bodily harm, is the most severe form of homicide. Washington law distinguishes between first-degree murder (RCW 9A.32.030), which requires premeditation, and second-degree murder (RCW 9A.32.050), which is intentional but without premeditation. Manslaughter in Washington is divided into first-degree manslaughter (RCW 9A.32.060), involving recklessness or disregard for life, and second-degree manslaughter (RCW 9A.32.070), involving criminal negligence. Additionally, vehicular homicide (RCW 46.61.520) is charged when a death is caused by someone driving a vehicle recklessly, under the influence of intoxicants, or with disregard for the safety of others. The specific charges and penalties for homicide offenses in Washington are detailed in the Revised Code of Washington (RCW), particularly in the sections related to criminal offenses.