The unlawful killing of another person, without justification, is referred to as “murder.” The crime of murder is considered by many, to be the most serious crime someone can commit. As such, an individual convicted of murder may be sentenced to serve many years in prison, to serve the rest of his life in prison without the possibility of being paroled, or may be sentenced to death. The exact legal definition of murder varies slightly by jurisdiction. To explore this concept, consider the following murder definition.

Definition of Murder


  1. The crime of deliberately and unlawfully killing a person.


  1. To kill a person inhumanly or barbarously.


1300-1350        Middle English murther

Murder Throughout History

The taking of another life without valid justification has been considered a crime deserving of the most severe punishment. Murder is seen, not only for its fundamental wrongness, but because of its cost to society as a whole. Taking another person’s life violates that individual’s right to life, is oppressive to others who may fear the same, causes grief, and robs society of the contributions that may have been made by the victim. For these reasons, murder has been punished severely to incapacitate or rehabilitate the offender, though more often harsh sentences are seen as retribution and a deterrent to others.

Historical Definition of Murder

Even today, the specific definition of murder varies in each jurisdiction. Under English Common Law, murder was defined as the unlawful killing of a person with “malice aforethought.” In this use, malice aforethought did not necessarily refer to a premeditated plan to kill, but a level of intent or recklessness that elevated the killing above other types of killings, such as accidental or in self-defense. With this classification, the killing reasonably required a severe punishment.

Over hundreds of years, the definition of murder has evolved. In most modern legal systems, the crime of murder is grouped into several classifications, including:

  1. Intentional Murder
  2. Murder resulting from an intentional action meant to cause serious bodily harm
  3. Murder resulting from extreme and wanton recklessness
  4. Murder by an accomplice as an individual commits, attempts to commit, or flees from the commission of a felony

Malice Aforethought

The legal term malice aforethought is used to describe the premeditation element required in some crimes. Premeditation, or malice aforethought, is also a singular element necessary for a charge of aggravated or first-degree murder. In the United States, intent not only refers to an individual’s pre-planning to take the life of another person, but can be inferred when the perpetrator acts with no respect or care for human life, or with gross recklessness. In many U.S. jurisdictions, a perpetrator who kills someone as the perpetrator flees from a felony, or from attempting to commit a felony, may be considered to have had malice aforethought, and be charged with murder.

Malice aforethought may also be assumed if a perpetrator had the intent to kill one person, but unintentionally killed another person instead. The intent to kill is sufficient to prove the malice aforethought, even if the perpetrator missed his target.

Murder, Homicide, and Manslaughter

The terms “murder” and “homicide” are sometimes used interchangeably, and often confused, but there is a difference between the two. A homicide is defined as the killing of one person by another person. The term includes, in addition to murder, killing by accident or in self defense. Murder is a form of criminal homicide in which the perpetrator had an intent to kill another person. Manslaughter is also a form of criminal homicide that has more to do with a disregard for human life than premeditation.

Involuntary Manslaughter

Causing a death while engaged in a reckless or unlawful activity that is not a felony may be considered involuntary manslaughter. For example, Nate is speeding on his way into town to meet some friends at the bar. When Nate loses control and slams into an oak tree, his roommate passenger is killed. Nate can be charged with involuntary manslaughter for causing his friend’s death through reckless driving.

Voluntary Manslaughter

Killing someone in the heat of passion, or during the commission of a felony, may be classified as voluntary manslaughter. For example, Nate and his roommate make it to the bar where their friends half already been drinking. Pete, one of Nate’s friends, says something offensive to Nate, and a fight ensues. Nate picks up a chair and slams it into Pete’s head, causing a serious head injury from which Pete later dies. Nate may be charged with voluntary manslaughter, as he intended to cause injury with the chair, the death occurred as a result of a felony.

Degrees of Murder

Even when considering how to prosecute and punish someone for killing another person, the law sees some of these crimes more despicable and dangerous than others. This leads to the classification of murder into categories, or “degrees” of murder. While some states define degrees of murder numerically, others use certain name labels specified in their statutes. No matter how murder is classified in each jurisdiction, the point is to increase the severity of punishment with the degree of the crime.

First Degree Murder

The specifics of what circumstances lead to a classification of first degree murder, also known as “capital murder,” vary by state, but the most common elements include:

  • The killing was premeditated and deliberate: The perpetrator had the intent to kill, and had time to contemplate the matter, if even for a brief time. This is referred to as malice aforethought.
  • The killing occurred during the course of committing another felony: Sometimes referred to as “felony murder,” the perpetrator can be charged with murder, even if he did not actually do the killing, if it occurred while he was committing another serious crime. Generally, the death must have been a foreseeable result of the initial crime.
  • The perpetrator’s motive: Certain motives, which refer to the perpetrator’s reason for killing, result in a higher degree of felony. Such malevolent motives may include racially motivated murder, or the killing of a police officer.
  • Special circumstances: Some states specify certain special circumstances as to how the murder occurred or was committed that raise the degree of the of crime to capital murder automatically. In some states, the application of special circumstances makes the crime eligible for the death penalty. These often include:
    • The killing of more than one person
    • The killing was combined with another violent felony, such as sexual assault
    • The killing was accomplished through lying in wait
    • The killing was committed by poison, beheading, or torture

Example of Premeditated Murder:

Nancy has discovered her husband, Ned, is cheating on her. She goes to the hardware store and purchases a box of rat poison. Over the next couple of days, Nancy puts the poison into her husband’s morning coffee, and he dies of internal bleeding. Not only did Nancy deliberately think about, plan, and follow through with murdering her husband, but because she used poison, special circumstances may apply, in addition to capital murder, in some states.

Example of Felony Murder:

Tony’s sister is killed by a drunk driver, and in his anger, Tony tracks down the perpetrator, and sets fire to his house. During the attempt to put the fire out, a heavy beam falls and traps a firefighter, who dies within minutes. Although Tony had no intention of killing the firefighter, or anyone else for that matter, the death was caused as a result of the dangerous felony Tony did commit. The fact that someone could be killed as a result of the fire was foreseeable, so Tony may be charged with felony murder.

Second Degree Murder

Second degree murder, sometimes referred to as “Murder 2,” is often viewed as mid-way between first degree murder and voluntary manslaughter. Second degree murder is a killing that was not planned or premeditated, nor was it committed in the “heat of passion.” Second degree murder is a killing caused by the offender’s dangerous acts, and his obvious lack of concern for the lives of others. Simply put, second degree murder cases involve the intentional killing of another person without planning to do so.

Example Second Degree Murder Case:

Jose, who has a hot temper, argues with his boss. The dispute suddenly escalates, and Jose reaches into his desk drawer, pulls out the hand gun he keeps there, and fires two quick shots into his boss’ chest, killing him. Because Jose had no intent to kill someone when he came to work that day, nor when he engaged in the argument with his boss, the killing was not premeditated. The act of picking up the gun and shooting another person was intentional, however, so this crime may be charged as second degree murder.

Open Murder

Rather than charging one of the degrees of murder up front, some states allow an offender to be charged with “open murder.” When an offender is first taken into custody, charging “open murder” enables prosecutors to keep their options open, essentially charging him with the highest degree of murder, as well as each lesser type of murder, including each alternative theory of murder. In some states, the charges will be more specifically stated prior to trial, in others, the case will be sent to the jury with the choice of convicting the offender on any type of murder.

Murder Trial

The basic elements of a murder trial are the same as for virtually any other felony trial. Because of the seriousness of the crime, and the severity of punishment should the accused be convicted, murder trials often take longer, and entail a great number of witnesses and larger volume of evidence to be presented. Basic trial procedure includes:

  1. Jury Selection – The attorneys and trial judge choose jurors from a randomly selected pool of available jurors. Potential jurors are questioned by each attorney to determine if any of them have a bias, prejudice, or personal interest in the case that may influence their decision. Those with a bias are dismissed.
  2. Opening Statements – At the beginning of the trial, each side verbally outlines the case, and the proof they intend to present during the trial. An opening statement is not testimony or evidence, but a brief description of what to expect during the course of the trial.
  3. Presentation of Witnesses and Evidence – The prosecution begins the trial by presenting its case against the defendant. Witnesses are called and questioned by the prosecution, then cross-examined by the defense, and evidence is presented and cataloged. Once the prosecution is finished, the defense takes over calling witnesses and presenting evidence in an attempt to disprove the alleged facts, or simply to create reasonable doubt as to the defendant’s guilt.
  4. Closing Arguments – After all evidence and witnesses have been presented, the attorneys each summarize the case, evidence, and testimony presented throughout the trial, lending a persuasive bent toward their side.
  5. Jury Instructions – Before the jury retires to consider the facts, the judge reads a set of instructions that state how the law should be applied to the case, defines all of the issues the jurors must decide, and other issues specific to the case.
  6. Deliberation – The jury moves to a private room to consider the evidence together, and reach a verdict. In a murder trial, the defendant must be found guilty beyond a reasonable doubt in order to be convicted. In most states, the vote of the jury must be unanimous for a conviction to occur.

Related Legal Terms and Issues

  • Beyond a Reasonable Doubt – The standard of proof required in a criminal trial: that no other logical explanation exists, given the facts presented, that the accused committed the crime.
  • Cross Examination – The interrogation or questioning of a witness called by the opposition, often for the purpose of discrediting the witness’ testimony.
  • Defendant – A party against whom a lawsuit has been filed in civil court, or who has been accused of, or charged with, a crime or offense.
  • Jurisdiction – The legal authority to hear legal cases and make judgments; the geographical region of authority to enforce justice.
  • Recklessness – Rash, careless, or wanton conduct that ignores the possibility of dangerous consequences.