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 Oklahoma, homicide is defined as the killing of one person by another and encompasses various levels of criminal culpability. Not all homicides are considered murder. Murder in Oklahoma is classified into first-degree and second-degree murder. First-degree murder involves premeditated intent to kill, while second-degree murder involves intent but without premeditation. Manslaughter in Oklahoma is divided into voluntary and involuntary manslaughter. Voluntary manslaughter occurs when a homicide is committed in the heat of passion, while involuntary manslaughter typically involves unintentional killing due to reckless or negligent behavior, such as vehicular homicide resulting from reckless driving or driving under the influence of drugs or alcohol. Oklahoma law also recognizes justifiable homicide, which includes killings in self-defense or defense of another person under certain circumstances. The specific charges and penalties for homicide offenses are detailed in Oklahoma's penal code, and they vary based on the circumstances and severity of the offense.