This list of unsolved murders includes notable cases where victims have been murdered under unknown circumstances.

Before 1800 Mawdud, 1113, atabeg of Mosul; stabbed to death in Damascus by an unidentified assailant. While the assassin himself was killed, the murder is believed to have been orchestrated by a third party whose identity was never discovered. Many at the time believed that Toghtekin, the ruler of Damascus, had arranged the murder for fear that Mawdud would usurp his authority, but there is no clear evidence of this. Other suspects include Fakhr al-Mulk Ridwan, the ruler of Aleppo, or members of the Order of Assassins who may have regarded Mawdud as a threat to them. Anselm Adornes (58) was slaughtered by a group of unknown assailants on 23 January 1483 while staying at a monastery at North Berwick. Giovanni Borgia, 2nd Duke of Gandía, 1497; his body was recovered from the Tiber with his throat slit and about nine stab wounds on his torso. His father, Pope Alexander VI, launched an investigation but it ended without results. Theories range from the Orsini family to Cardinal Ascanio Sforza, and even to his own brother, Cesare Borgia, having committed the crime. Richard Hunne, an English merchant accused of heresy, was found hanging in his cell in St. Paul's Cathedral on 4 December 1514. Although his death was staged as a suicide, a coroner's jury found that he had been murdered due to evidence that it was physically impossible for him to have hanged himself; however, the sole suspects were never brought to trial due to judicial interference. Robert Pakington (46–47), 1536, likely to have been the first person murdered with a handgun in London. John Knight was a British explorer who disappeared after his boat went over a hill most likely near NainLaughton, John Knox (1892). "Knight, John (d.1606)". In Lee, Sidney (ed.). Dictionary of National Biography. Vol. 31. London: Smith, Elder & Co. pp. 254–255. on 23 or 24 June 1606. Some time after that it was confirmed that he had been killed by local residents, but these people were never identified and no one was charged with his murder. Expatriate English Royalists are believed to have ambushed and murdered Isaac Dorislaus in 1649,Spencer, Charles, Killers of the King: The Men Who Dared to Execute Charles I p 33 then a diplomat representing the interests of the Commonwealth to the Dutch government at The Hague, in retaliation for his role in the trial and execution of Charles I. No suspects were ever identified, although some Royalists later boasted of having taken part. Sir Edmund Berry Godfrey (56), in 1678; he was found impaled on his own sword and strangled at Primrose Hill, London.Kenyon, J.P. (2000). The Popish Plot. Phoenix Press reissue. Three men were hanged, but later the witness' statement was found to be perjured. Alessandro Stradella (38), 1682, composer; he was stabbed to death at the Piazza Banchi of Genoa. His infidelities were well known, and many theorize that a nobleman of the Lomellini family hired the killer. Jean-François Duclerc, a French privateer who was murdered in Rio de Janeiro on 18 March 1711 while he was in prison for unknown reasons by masked gunmen.Henri Malo, yksityisasiamies Landolphe: seurasi Du Clerc à Rio-de-Janeiro (1710), Maritime League,1943, 107 Sivumäärä, -8, 15 x 24 cm, s. 99 - 106. The case was never solved. Jean-Marie Leclair (67), 1764, violinist and composer; he was found stabbed in his Paris home. Although the murder remains a mystery, his nephew, Guillaume-François Vial, and Leclair's ex-wife were considered main suspects at the time. Although the colonial authorities in Pennsylvania at the time investigated the two December 1764 Paxton Boys massacres of defenseless Conestoga communities near present-day Millersville as a criminal mass murder, the perpetrators were never identified. Gulielma "Elma" Sands (22) disappeared on the evening of 22 December 1799 in Manhattan. Her body was recovered from the newly created Manhattan Well in January the following year. Circumstantial evidence led to the prosecution of her lover Levi Weeks, but he was acquitted after a vigorous defence by Aaron Burr, Alexander Hamilton and Henry Brockholst Livingston.

1800s Police constable Joseph Luker was beaten to death in Sydney on the night of 25–26 August 1803. The crime was believed to be related to a robbery earlier that night which Luker had been investigating. Suspicion fell on two fellow constables whom Luker had accused of involvement in the robbery, but both men were acquitted; one suspect, Joseph Samuel, was found guilty of the robbery but was never charged with the murder. Dominic Daley and James Halligan were convicted of the murder of Marcus Lyon, a farmer who was found beaten and shot near Wilbraham, Massachusetts on 5 November 1805. There was very little evidence against the two men and the consensus of historians is that they were innocent and were convicted largely due to anti-Irish bigotry; both were legally exonerated in 1984, over a century after their execution. It remains uncertain who killed Marcus Lyon, although one theory points to a relative of the prosecution's main witness. Joseph Hedley (76), was a Quilter from Northumberland, who was killed in his home on 3 January 1826. Despite a large reward being offered, the culprits remain unknown. Elijah Parish Lovejoy (34), was an American Presbyterian minister, journalist, newspaper editor, and abolitionist. He was shot and killed on 7 November 1837 by a pro-slavery mob in Alton, Illinois, during their attack on the warehouse of Benjamin Godfrey and W. S. Gillman to destroy Lovejoy's press and abolitionist materials. Helen Jewett (22), American sex worker who was murdered in New York City on 10 April 1836. A young man named Richard P. Robinson was arrested and charged with her murder, but was found not guilty.Ramsland, Katherine. "The sensational murder of Helen Jewett, gorgeous NY prostitute". Crime Library. Archived from the original on 2 May 2014. Retrieved 31 March 2018. The real killer was never found. John Bibby (65), founder of the Bibby Shipping Line, was found dead in a pond on July 17, 1840. His cause of death was recorded as drowning. It was believed that he had been killed in a robbery as his valuable watch had been stolen from his body. Only one suspect was identified but there was not enough evidence to charge him and the killing remained unsolved; Merseyside Police still consider the case open. Mary Rogers (21–22), also known as the "Beautiful Cigar Girl"; her body was found in the Hudson River on 28 July 1841. The story became a national sensation and inspired Edgar Allan Poe to write "The Mystery of Marie Rogêt" (1842). Amasa Sprague (45) was shot and beaten to death by two or three men on 31 December 1843 in Knightsville, Rhode Island. Of the three men tried, only one, John Gordon, was found guilty; he was exonerated posthumously in 2011.Erika Niedowski, "RI governor pardons Irish man hanged in 1845", Associated Press, 2011-06-29. Joseph Smith (38), founder of the Church of Jesus Christ and Latter Day Saints, and his brother Hyrum Smith (44) were killed on 27 June 1844 when a mob stormed the jail in Carthage, Illinois where they were awaiting trial for treason and shot both of them to death. Five suspects stood trial but were acquitted, and several others had fled to Missouri before they could be arrested. Françoise de Choiseul-Praslin, wife of French duke Charles de Choiseul-Praslin; she died shortly after a beating and stabbing in the family's Paris apartment on 17 August 1847. Her husband was arrested, but committed suicide during trial, protesting his innocence all along. No other suspect has ever been identified. The scandal caused by the case helped to provoke the French Revolution of 1848. Bohlke Luerssen (52) well-known German immigrant, engaged in distilling and manufacturing syrups and cordials at No.101 North Monroe street, New York, he was found floating in the water wedged between some rocks and the sea-wall, within a few rods of Sibyl's Cave, in Hoboken on 21 December 1859. His killer was suspected to be a former employee of his by the name of John Schuman that he fired for dishonesty. John Schuman was never tried as a suspect due to no evidence being found. Barbu Catargiu (54), the first Prime Minister of Romania and a conservative politician, was assassinated during a parliamentary meeting on June 20, 1862. His killer was never found.Maria Nikolaeva Todorova, Balkan Identities: Nation and Memory (New York: NYU Press, 2004), p. 289 John Bozeman (32), an American frontiersman who helped establish the Bozeman Trail and founded the city Bozeman, Montana, was killed under unclear circumstances along the Yellowstone River on April 20, 1867. Various theories have been proposed concerning his death, ranging from an attack by Blackfeet Indians to revenge for his flirting with women.Goodman, Kent. "The Real John Bozeman: with sneaky ways and low morals," February 1, 2015. https://bozemanmagazine.com/articles/2015/02/01/101576-the-real-john-bozeman-with-sneaky-ways-and-low. Sakamoto Ryōma (31) and Nakaoka Shintarō (29) were Japanese samurai who figured prominently in the movement to overthrow the Tokugawa shogunate.National Diet Library (NDL), Portraits of Modern Japanese Historical Figures, Nakaoka, Shintaro On the night of 10 December 1867, Sakamoto, Nakaoka, and Yamada Tōkichi (Sakamoto's bodyguard) were attacked at Kyoto's Ōmiya Inn by pro-shogunate assassins. All three died of their injuries; only Nakaoka, who lived for two days after, was able to provide any clues, saying that the killers spoke the Iyo dialect. Officially, the Shinsengumi, the shogunate's special police force, were blamed, with its commander, Kondō Isami, being executed for the murders in 1868. However, in 1870, members of the Mimawarigumi, another special police force, claimed that they had, in fact, carried out the killings. Due to this uncertainty, the murders are considered unsolved.Gombrich, Marius, "Crime scene investigation: Edo: Samurai Sakamoto Ryoma's murder scene makes a grisly but fascinating show", Japan Times, 7 May 2010, p. 15. George W. Ashburn (53), an American Radical Republican politician in Georgia, was assassinated by members of the Ku Klux Klan on 31 March 1868. Twenty people were accused of involvement in Ashburn's murder, but political interference by Georgia legislators resulted in all suspects being released.

T. C. Hindman (40), an American politician assassinated by one or more assailants on 27 September 1868. The assassins fired through the parlor window of his home while he was reading the newspaper with his children in Helena, Arkansas. Alexander Boyd (35), the county solicitor of Greene County, Alabama, was lynched by the Ku Klux Klan on 31 March 1870. Benjamin Nathan (56), a financier turned philanthropist; was found beaten to death in his New York City home on 28 July 1870. Several suspects were identified, including Nathan's profligate son Washington, who discovered the body along with his brother, but no one was ever indicted. Juan Prim (56), a Spanish general and statesman; in December 1870, he was shot through the windows of his carriage by several assailants and died two days later. In 2012, his body was exhumed; the autopsy showed he may have been strangled on his deathbed, but results were deemed inconclusive. Sharon Tyndale (65), former Illinois Secretary of State, was robbed and shot as he walked from his house in Springfield to the nearby train station early on the morning of 29 April 1871.