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 Oklahoma, murder is defined under the state's penal code and is categorized into degrees. First-degree murder, as per Oklahoma statutes, involves a premeditated intent to cause the death of another person, which aligns with the historical concept of 'malice aforethought.' This is the most serious form of homicide and can result in the death penalty or life imprisonment without parole. Second-degree murder in Oklahoma is an intentional killing that is not premeditated or planned in advance. Oklahoma also recognizes the offense of 'manslaughter,' which is a less severe form of homicide involving killings that are either unintentional but reckless (first-degree manslaughter) or committed in the 'heat of passion' (second-degree manslaughter). Capital murder, which is not a separate category in Oklahoma, would typically fall under first-degree murder and includes circumstances such as killing a law enforcement officer or committing murder for hire, which can lead to the death penalty.