Murder is the unlawful killing of another human without justification or valid excuse, especially the unlawful killing of another human with malice aforethought. This state of mind may, depending upon the jurisdiction, distinguish murder from other forms of unlawful homicide, such as manslaughter. Manslaughter is killing committed in the absence of malice, brought about by reasonable provocation, or diminished capacity. Involuntary manslaughter, where it is recognized, is a killing that lacks all but the most attenuated guilty intent, recklessness.
In criminal law, diminished responsibility is a potential defense by excuse by which defendants argue that although they broke the law, they should not be held fully criminally liable for doing so, as their mental functions were "diminished" or impaired.
The rule of felony murder is a legal doctrine in some common law jurisdictions that broadens the crime of murder: when someone is killed in the commission of a dangerous or enumerated crime, the offender, and also the offender's accomplices or co-conspirators, may be found guilty of murder.
In United States law, depraved-heart murder, also known as depraved-indifference murder, is a type of murder where an individual acts with a "depraved indifference" to human life and where such act results in a death, despite that individual not explicitly intending to kill. In a depraved-heart murder, defendants commit an act even though they know their act runs an unusually high risk of causing death or serious bodily harm to a person. If the risk of death or bodily harm is great enough, ignoring it demonstrates a "depraved indifference" to human life and the resulting death is considered to have been committed with malice aforethought. In some states, depraved-heart killings constitute second-degree murder, while in others, the act would be charged with "wanton murder", varying degrees of manslaughter, or third-degree murder.
Malice aforethought is the "premeditation" or "predetermination" required as an element of some crimes in some jurisdictions and a unique element for first-degree or aggravated murder in a few. Insofar as the term is still in use, it has a technical meaning that has changed substantially over time.
A stand-your-ground law, sometimes called a "line in the sand" or "no duty to retreat" law, provides that people may use deadly force when they reasonably believe it to be necessary to defend against certain violent crimes. Under such a law, people have no duty to retreat before using deadly force in self-defense, so long as they are in a place where they are lawfully present. The exact details vary by jurisdiction.
Most jurisdictions in the United States of America maintain the felony murder rule. In essence, the felony murder rule states that when an offender kills in the commission of a dangerous or enumerated crime, the offender, and also the offender's accomplices or co-conspirators, may be found guilty of murder. It means that the common law malice required for murder is "implied as a matter of law for homicides arising from felonies." It is a widely criticized feature of American criminal law. Initially, it was widely believed by scholars that the felony murder rule had originated in England. However, more recent scholarship has argued that it likely originated in America separately from England. Its historic roots have been called "deep but terribly obscure".
Manslaughter is a common law legal term for homicide considered by law as less culpable than murder. The distinction between murder and manslaughter is sometimes said to have first been made by the ancient Athenian lawmaker Draco in the 7th century BC.
Bigby v. Dretke 402 F.3d 551, the U.S. Court of Appeals for the Fifth Circuit heard a case appealed from the United States District Court for the Northern District of Texas on the issue of the instructions given to a jury in death penalty sentencing. The decision took into account the recent United States Supreme Court decisions concerning the relevance of mitigating evidence in sentencing, as in Penry v. Lynaugh.
Imperfect self-defense is a common law doctrine recognized by some jurisdictions whereby a defendant may mitigate punishment or sentencing imposed for a crime involving the use of deadly force by claiming, as a partial affirmative defense, the honest but unreasonable belief that the actions were necessary to counter an attack. Not all jurisdictions accept imperfect self-defense as a basis to reduce a murder charge.
In criminal law, a lesser included offense is a crime for which all of the elements necessary to impose liability are also elements found in a more serious crime. It is also used in non-criminal violations of law, such as certain classes of traffic offenses.
People v. Berry is a voluntary manslaughter case that is widely taught in American law schools for the appellate court's unusual interpretation of heat of passion doctrine. Although the defendant had time to "cool down" between his wife's verbal admission of infidelity and the killing, the California Supreme Court held that the provocation in this case was adequate to reduce a murder charge to manslaughter. The lower court had relied on the traditional definition of "adequate provocation" in its jury instructions. The California Supreme Court reversed Berry's murder conviction, while affirming Berry's conviction for assault using deadly force.
In the United States, the law for murder varies by jurisdiction. In many US jurisdictions there is a hierarchy of acts, known collectively as homicide, of which first-degree murder and felony murder are the most serious, followed by second-degree murder and, in a few states, third-degree murder, which in other states is divided into voluntary manslaughter, and involuntary manslaughter such as reckless homicide and negligent homicide, which are the least serious, and ending finally in justifiable homicide, which is not a crime. However, because there are at least 52 relevant jurisdictions, each with its own criminal code, this is a considerable simplification.
In the state of California, a heavily modified version of the common law felony murder rule is codified in California Penal Code § 189.
Leland v. Oregon, 343 U.S. 790 (1952), was a United States Supreme Court case in which the Court upheld the constitutionality of placing the burden of persuasion on the defendant when they argue an insanity defense in a criminal trial. This differed from previous federal common law established in Davis v. United States, in which the court held that if the defense raised an insanity defense, the prosecution must prove sanity beyond a reasonable doubt, but Davis was not a United States constitutional ruling, so only limited federal cases, but not state cases. Oregon had a very high burden on defense, that insanity be proved beyond a reasonable doubt. At that time, twenty other states also placed the burden of persuasion on the defense for an insanity defense.
Criminal law is a system of laws that is connected with crimes and punishments of an individual who commits crimes. In comparison, civil law is where the case argues their issues with one entity to another entity with support of the law. Crimes can vary in definition by jurisdiction but the basis for a crime are fairly consistent regardless.
Murder in Pennsylvania constitutes the intentional killing, under circumstances defined by law, of people within or under the jurisdiction of the U.S. state of Pennsylvania.
English law contains homicide offences – those acts involving the death of another person. For a crime to be considered homicide, it must take place after the victim's legally recognised birth, and before their legal death. There is also the usually uncontroversial requirement that the victim be under the "Queen's peace". The death must be causally linked to the actions of the defendant. Since the abolition of the year and a day rule, there is no maximum time period between any act being committed and the victim's death, so long as the former caused the latter.
People v. Newton, 8 Cal. App. 3d 359, was a controversial appeal arising from the voluntary manslaughter conviction of Huey P. Newton, the reputed co-founder of the Black Panther Party for Self Defense. The California Court of Appeal reversed Newton's conviction due to prejudicial error stemming from the trial court's failure to instruct the jury as to the possibility of involuntary unconsciousness as a complete defense to the charges. Though Newton's attorney arguably withdrew the defense at trial, the Court nonetheless held that the failure to instruct violated Newton's constitutional right to have the jury determine all material issues based on the evidence. This case stands for the proposition that trial courts have an affirmative duty to instruct juries as to a defense of involuntary unconsciousness where there exists evidence that may support that conclusion.
Blueford v. Arkansas, 566 U.S. 599 (2012), was a decision of the Supreme Court of the United States that clarified the limits of the Double Jeopardy Clause. The Supreme Court held that the Double Jeopardy Clause does not bar retrial of counts that a jury had previously unanimously voted to acquit on, when a mistrial is declared after the jury deadlocked on a lesser included offense.
