Murder

• 1. Introduction

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  Murder sits at the center of almost every legal system ever devised by human beings. Across cultures, centuries, and continents, societies have wrestled with a single hard question: when does one person's killing of another cross a line so severe that the community must respond with its most serious punishment? The modern English word itself descends from the Proto-Indo-European root meaning "to die," a linguistic thread running from ancient languages all the way into courtrooms today. But the word is far older than any statute. One of the oldest-known prohibitions against murder appears in the Sumerian Code of Ur-Nammu, written sometime between 2100 and 2050 BC. It states simply: "If a man commits a murder, that man must be killed." Four thousand years of legal evolution have made the question far more complicated than that. What counts as murder? When does killing become justified? And how has the way we answer those questions changed across human history?

• 2. What the Law Requires

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  The eighteenth-century English jurist William Blackstone, citing Edward Coke, laid out what would become the template for the common law definition of murder. In his Commentaries on the Laws of England, he wrote that murder occurs when a person of sound memory and discretion unlawfully kills any reasonable creature in being and under the king's peace, with malice aforethought, either express or implied. Each word in that formulation carries weight. "Unlawful" separates murder from state-sanctioned killing such as capital punishment or the lawful killing of enemy combatants in war. "Killing" itself has a precise meaning: at common law, life ended with the total and irreversible cessation of blood circulation and respiration. Medical advances eventually led courts to adopt a different standard, treating irreversible cessation of all brain function as the end of life. "Of a human" raised the question of when life begins. At common law, a fetus was not considered a human being; life started when the fetus passed through the birth canal and took its first breath. Suicide, in early common law, was actually classified as murder, a view later abandoned since the law required the victim to be someone other than the perpetrator. The phrase "malice aforethought" originally meant exactly what it sounds like: a deliberate and premeditated killing motivated by ill will, with an appreciable time required between forming the intent and carrying it out. Courts later broadened this concept significantly, eliminating the requirement for actual premeditation. The legal question shrank to whether the perpetrator acted with one of four recognized states of mind constituting malice. Under what is called the "abandoned and malignant heart" standard, killing can result from reckless indifference to human life and a conscious disregard of an unreasonable risk of death or serious injury. The so-called felony murder doctrine goes further still: if a person kills during the commission of an inherently dangerous felony such as burglary, arson, rape, robbery, or kidnapping, they may be convicted of murder regardless of intent.

• 3. Degrees, Defenses, and Exceptions

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  Canada and the United States both recognize a distinction between first- and second-degree murder. Generally, second-degree murder maps onto the common law baseline, while first-degree carries additional aggravating factors such as premeditation, deliberation, or specific methods like poisoning or lying in wait. A handful of US states go further, recognizing third-degree murder: Minnesota and Pennsylvania define it as depraved-heart murder, while Florida defines it as felony murder not covered by first-degree. In the Netherlands, the only factor separating murder from manslaughter is the existence of premeditation; manslaughter with aggravating factors may be punished more harshly but is never classified as murder. Spain introduced its own framework in its Criminal Code, last reformed and in force since the 1st of July 2015. Under Spanish law, homicide becomes assassination when accompanied by treachery, financial gain, viciousness in increasing the victim's suffering, or an intent to facilitate or conceal another crime. The law also carves out substantial room for defenses. A defendant whose mental state at the time of the killing rendered them unable to distinguish right from wrong may plead not guilty by reason of insanity. New York law specifically requires that the mental disease or defect left the defendant without substantial capacity to know the nature of their conduct or that it was wrong. The French Penal Code, under Article 122-1, distinguishes between a disorder that entirely destroyed the defendant's discernment, which eliminates criminal liability, and one that merely reduced it, which keeps the person punishable but requires the court to account for it in sentencing. Those who succeed with an insanity defense are typically referred to mandatory clinical treatment rather than prison. Postpartum depression has received specific recognition in some countries. According to researcher Susan Friedman, roughly two dozen nations have enacted infanticide laws that reduce penalties for mothers who kill their children in the first year of life. Ireland made infanticide a separate offense from murder in 1949, covering cases where the balance of the mother's mind was disturbed by the effects of childbirth or lactation. Russia created a parallel separate offense for newborn homicide by the mother in 1996. The diminished capacity defense has produced some of the most contested outcomes in American legal history. In California, Dan White used it to secure a manslaughter conviction rather than murder in the killings of Mayor George Moscone and Supervisor Harvey Milk. The public reaction was sharp enough that California subsequently amended its penal code to eliminate diminished capacity, diminished responsibility, and irresistible impulse as defenses in criminal cases.

• 4. Ancient Attitudes, Ritual Killing, and Honor

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  Scholar Georg Oesterdiekhoff drew on the fieldwork of Evans-Pritchard to describe the Nuer people of Sudan, noting that homicide was not forbidden among them and that killing a man in fair fight was admired rather than condemned. This was not an isolated phenomenon. According to ethnographic accounts, similar attitudes prevailed among pre-modern Europeans, Indigenous Australians, and Native Americans, as well as headhunter cultures in Papua, where killing was tied directly to life milestones: a father had to kill a man to obtain a name for his newborn son, and a man had to kill before he could marry. Where legal systems did not exist to adjudicate these killings, blood revenge served as the primary mechanism for redress. In early Germanic society, a payment called the weregild could be offered to the victim's family in lieu of revenge, an early attempt to convert lethal cycles of vengeance into something more structured. Religious traditions imposed their own prohibitions. In the Abrahamic faiths, the first murder in scripture is Cain killing his brother Abel out of jealousy. The prohibition against murder appears explicitly in the Ten Commandments given to Moses, recorded in both Exodus and Deuteronomy. The Quran identifies killing an innocent human being as one of the greatest sins in Islam. At the same time, organized killing for religious or political purposes has a long and documented history. The term assassin derives from Hashshashin, a militant Ismaili Shi'ite sect active from the 8th to 14th centuries. This secret society killed members of the Abbasid, Fatimid, Seljuq, and Crusader elites for political and religious ends. The Thuggee cult in India, devoted to Kali, the goddess of death and destruction, is estimated by some accounts to have murdered one million people between 1740 and 1840. The Aztec belief that the sun god Huitzilopochtli required regular blood offerings led to mass sacrifices: according to historian Ross Hassig, between 10,000 and 80,400 persons were sacrificed during the 1487 re-consecration of the Great Pyramid of Tenochtitlan. In Corsica, a social code called vendetta required families to kill anyone who wronged their honor. Between 1821 and 1852, no fewer than 4,300 murders were recorded there under this code.

• 5. How Murder Rates Have Shifted

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  Scholar Pieter Spierenburg traced homicide rates across Europe over the long span of recorded history. In medieval times, the rate sat at roughly 35 per 100,000 people. By 1500 it had fallen to around 20. By 1700 it had dropped to five. By 1900, it was below two per 100,000. The United States followed a different and more volatile path. The rate fell below 2 per 100,000 by 1900, rose during the first half of the twentieth century, dropped after World War II, and reached a low of 4.0 in 1957 before climbing again. Through much of the period from 1972 to 1994, it stayed in the 9 to 10 range per 100,000. A significant factor in the World War II-era decline across developed countries was demographic: because most murders are committed by young males, the low birth rates of the Great Depression and the war years reduced the pool of potential perpetrators around 1960. Rising rates in the early twentieth century in the US are widely attributed to gang violence during Prohibition. Two more exotic hypotheses have been proposed for later shifts: the availability of abortion, and childhood exposure to lead from leaded paint and tetraethyllead gasoline additives. Medical progress has quietly altered what the murder rate measures. One estimate suggests that if the lethality of criminal assaults in 1964 had persisted into 1993, the US murder rate would have reached roughly 26 per 100,000, nearly triple the actually observed rate of 9.5. Improvements in trauma care and emergency response transformed would-be murders into assaults survived. Latin America and the Caribbean have seen the highest murder rates in the contemporary world, recording more than 2.5 million murders between 2000 and 2017. Honduras topped global rankings with a rate of 91.6 per 100,000, according to a 2011 UN Office on Drugs and Crime survey. The World Health Organization reported in October 2002 that a person was being murdered every 60 seconds. An estimated 520,000 people were killed worldwide in 2000; a separate study put the figure at 456,300 in 2010, representing a 35 percent increase since 1990. Two-fifths of those victims were young people between the ages of 10 and 29.

• 6. Investigation, Clearance, and Limits of Justice

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  Despite major advances in forensics over recent decades, the fraction of murders solved in the United States has actually fallen. In 1960, roughly 90 percent of murder cases were cleared. By 2007, that figure had dropped to 61 percent. Within major cities the variation was stark: in that same year, the clearance rate ranged from 36 percent in Boston, Massachusetts, to 76 percent in San Jose, California. The main factors driving that gap are witness cooperation and the number of investigators assigned to each case. One procedural rule that shaped murder law for centuries is the year-and-a-day rule: under this doctrine, if a victim survived more than a year and a day after an attack, the attacker could not be charged with murder. England and Wales abolished this rule through the Law Reform (Year and a Day Rule) Act 1996, though it introduced a safeguard: if death occurs three or more years after the original attack, prosecution requires the attorney-general's approval. In 2001, the Supreme Court of the United States held that retroactive elimination of the rule by a state court did not violate the Constitution's Ex Post Facto Clause. The practical stakes of that ruling can be seen in the case of William Barnes, who was 74 years old when he was charged with the murder of Philadelphia police officer Walter T. Barclay Jr. Barnes had shot Barclay nearly 41 years earlier and had already served 16 years in prison for the attempt. When Barclay died on the 19th of August 2007, allegedly from complications of those old wounds, Barnes faced a new murder charge. He was acquitted on the 24th of May 2010. Because murder is the least likely crime to go unreported, criminologists treat murder statistics as a reliable indicator of overall violence levels in a society, even as the clearance rate continues its long decline.