Murder is the intentional, premeditated killing of another human being. The premeditation requirement for murder was historically described in the law as “malice aforethought.”

Laws regarding murder vary from state to state, and some states have a separate criminal offense of capital murder, which usually involves the most egregious circumstances, such as killing a peace officer in the line of duty or lying in wait to ambush and kill the victim. Capital murder offenses carry a potential death penalty.

And some states use the distinction of first degree murder (done with premeditation and punishable by death or life in prison) and second degree murder (generally an intentional killing without premeditation—also known as manslaughter or voluntary manslaughter in some states).

The criminal offense of murder is generally located in a state’s statutes—often in the penal or criminal code.

In Arizona, murder is classified into different degrees with specific criteria for each. First-degree murder, as defined by Arizona Revised Statutes § 13-1105, is a premeditated act, meaning that the individual accused of the crime intended to kill and planned it beforehand. This is the most serious form of homicide and can result in the death penalty or life imprisonment. Arizona does have the death penalty, and certain aggravating factors can make a first-degree murder eligible for capital punishment. Second-degree murder, under Arizona Revised Statutes § 13-1104, does not require premeditation but involves the intentional killing of another person without lawful justification. Second-degree murder is typically punishable by a lengthy prison sentence but does not carry the death penalty. Manslaughter, as per Arizona Revised Statutes § 13-1103, is a lesser offense that involves the reckless or sudden heat of passion killing of another person and carries its own set of penalties. It's important to note that the specific circumstances of a crime and the presence of any aggravating or mitigating factors can significantly influence the charges and penalties in a murder case.