The law for murder in the United States varies by state, each with its own criminal code, but these are some of the main classifications of homicide acts within US law.

First-degree murder

The premeditated, unlawful, intentional killing of another person.

Second-degree murder

The intentional, unlawful killing of another person, but without premeditation.

Felony murder

When someone is killed (regardless of the intent to kill) during the commission of a dangerous or enumerated crime.

Third-degree murder

Otherwise classified as manslaughter (killing without the intention to kill) in other jurisdictions.

Voluntary Manslaughter

The offender had the intent to kill or seriously harm, but acted ‘in the moment’ under circumstances that could cause a reasonable person to become mentally disturbed.

Involuntary Manslaughter

The killing of a human being without intent to do so. Distinguished from voluntary manslaughter by the absence of intention. It is often divided into constructive manslaughter and criminally negligent manslaughter.

Constructive Manslaughter / Unlawfully Act Manslaughter

When someone kills, without intent, in the course of committing an unlawful act.

Criminally Negligent

Where there is a failure to act when there is a duty to do so, which leads to death.

Assisted Suicide

Suicide committed with the aid of another person, possibly a medical professional.

Culpable Homicide

Killing a person either with or without the intention to kill. This definition varies depending on the particular jurisdiction has defined the offence.

Reckless Homicide

When the perpetrator was aware that their act creates a significant risk of death or grievous bodily harm and a human death occurs as a result.

Negligent Homicide

Similar to reckless homicide, but where the perpetrator did not have awareness of the risk of causing death, but should have done.

Justifiable Homicide

A defence to culpable homicide (otherwise know as self-defence). The subject has to be able to prove that he/she believed there was an imminent and otherwise unavoidable danger of death or grave bodily harm to them by the deceased when thy committed the homicide.