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 Wyoming, homicide is defined as the unlawful killing of one person by another. Wyoming law distinguishes between different types of homicide, including murder and manslaughter, based on the circumstances and the intent of the perpetrator. Murder is typically charged when the act is intentional and premeditated, falling under first-degree murder, or when it is intentional but without premeditation, known as second-degree murder. Manslaughter in Wyoming is divided into voluntary and involuntary manslaughter. Voluntary manslaughter occurs when a homicide is committed in a sudden heat of passion, while involuntary manslaughter is usually the result of negligent actions, such as reckless driving or driving under the influence, that lead to someone's death. Wyoming statutes provide specific definitions and penalties for these offenses, and affirmative defenses like self-defense or insanity may be applicable in certain cases to justify the act or mitigate the charges.