In Great Britain, this offence was created by section 5 of the Homicide Act 1957. Previously all murders carried the death penalty on conviction, but the 1957 Act limited the death penalty to the following cases:
Murder by shooting or by causing an explosion; s.5
Murder in the course or for the purpose of resisting, avoiding or preventing a lawful arrest, or of effecting or assisting an escape or rescue from legal custody; s.5
Murder of a police officeracting in the execution of his duty, or of a person assisting a police officer so acting; s.5
Murder of a prison officer acting in the execution of his duty, or of a person assisting a prison officer so acting, by a person who was a prisoner at the time when he did or was a party to the murder; s.5.
In all other cases murder carried the mandatory penalty of imprisonment for life. Section 1 of the Murder Act 1965 abolished the separate category of capital murder, and all murders now carry the mandatory penalty of imprisonment for life.
Northern Ireland
In Northern Ireland, this offence was created by section 10 of the Criminal Justice Act 1966. On the trial of an indictment for capital murder, the jury could not return an alternative verdict to the offence charged in that indictment under section 6 of the Criminal Law Act 1967. Sections 1 and of the Northern Ireland Act 1973 read:
The term "capital murder" is used in only eight U.S. states; however, 29 states and United States federal government currently allow capital punishment, and each has its own terminology for an offense punishable by death. In most states, the term "First-Degree Murder" is used; others may use the term "Aggravated Murder", and some use simply "Murder". The eight states that use the term "Capital Murder" are Alabama, Arkansas, California, Kansas, Mississippi, New Hampshire, Texas, and Virginia. The state of Georgia uses the term "Malice Murder". Not all offenses are parallel between the states. In some, first-degree murder is a very broad term defined by a number of circumstances, only a few of which make a defendant eligible for execution. In other jurisdictions, an offense carrying the death penalty is strictly defined and is separate from other, similar crimes. Although legal definitions vary, capital murder in the United States usually means murder involving one or more of the following factors:
The victim is a police officer, firefighter, paramedic or similar public safety professional and was killed while on duty
The victim is killed during the commission of another violent felony, such as armed robbery, kidnapping, arson, etc.
The victim is tortured, raped or sexually assaulted, particularly if the victim is a child
Multiple murders are committed pursuant to one another
The victim is murdered based on race, national origin, and other associated groups
Some states may include other factors which amount to capital murder or its legal equivalent.
Punishment
Capital offenses in the United States are not punishable by death exclusively. Most states afford courts the option of imposing either the death penalty or a life sentence upon conviction, though lesser sentences are rare and in some cases legally impossible. Depending on the state, the presiding judge may determine the sentence, or the decision may be left to the jury. The United States Supreme Court has placed limitations on the use of the death penalty and has prohibited its use in cases where the offender is mentally incompetent, or was under the age of 18 at the time of the offense.
