This list of unsolved murders includes important cases where victims were killed, but the reasons for the murders are not known.

Before 1800

• Anselm Adornes (58) was killed by a group of unknown attackers on 23 January 1483 while staying at a monastery in North Berwick.
• Giovanni Borgia, 2nd Duke of Gandía, in 1497; his body was found in the Tiber with his throat cut and nine stab wounds on his torso. His father, Pope Alexander VI, started an investigation, but it did not find any answers. Some people think members of the Orsini family, Cardinal Ascanio Sforza, or his brother, Cesare Borgia, may have 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 made to look like a suicide, a coroner's jury said he was murdered because it was impossible for him to have hanged himself. However, no suspects were ever brought to trial due to judicial interference.
• Robert Pakington (46–47), in 1536, was likely the first person murdered with a handgun in London.
• John Knight, a British explorer, disappeared after his boat went over a hill near Nain on 23 or 24 June 1606. Later, it was confirmed he was 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 attacked and killed Isaac Dorislaus in 1649. Dorislaus was a diplomat representing the Commonwealth to the Dutch government in The Hague. He was killed in retaliation for his role in the trial and execution of Charles I. No suspects were ever identified, although some Royalists later claimed they were involved.
• Sir Edmund Berry Godfrey (56), in 1678; he was found with his sword stuck through his body and strangled at Primrose Hill, London. Three men were hanged, but later it was discovered that the witness had lied in their statement.
• Alessandro Stradella (38), in 1682, a composer; he was stabbed to death at the Piazza Banchi of Genoa. He was known for having many romantic relationships, and some believe a nobleman from the Lomellini family hired the killer.
• Jean-François Duclerc, a French privateer, was murdered in Rio de Janeiro on 18 March 1711 while in prison for unknown reasons by masked gunmen. The case was never solved.
• Jean-Marie Leclair (67), in 1764, a 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.
• The colonial authorities in Pennsylvania investigated the two December 1764 Paxton Boys massacres of defenseless Conestoga communities near present-day Millersville as a criminal mass murder, but 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 strong defense by Aaron Burr, Alexander Hamilton, and Henry Brockholst Livingston.

1800s

• Dominic Daley and James Halligan were found guilty of killing Marcus Lyon, a farmer who was discovered beaten and shot near Wilbraham, Massachusetts, on November 5, 1805. There was little evidence against them, and many historians believe they were not guilty and were convicted because of prejudice against people from Ireland. Both men were officially proven not guilty in 1984, more than 100 years after they were executed. It is still unknown who killed Marcus Lyon, though one idea suggests it might have been a relative of the main witness in the case.
• Joseph Hedley (76), a quilter from Northumberland, was killed in his home on January 3, 1826. A reward was offered for information, but the people responsible were never identified.
• Elijah Parish Lovejoy (34), an American Presbyterian minister, journalist, newspaper editor, and abolitionist, was shot and killed on November 7, 1837, by a group that supported slavery in Alton, Illinois. The group attacked a warehouse to destroy Lovejoy’s printing press and materials against slavery.
• Helen Jewett (22), an American sex worker, was murdered in New York City on April 10, 1836. A man named Richard P. Robinson was arrested and charged with her murder but was found not guilty. The real killer was never discovered.
• John Bibby (65), founder of the Bibby Shipping Line, was found dead in a pond on July 17, 1840. His death was recorded as drowning, though it was believed he was killed during a robbery because his valuable watch was missing. One suspect was identified, but there was not enough evidence to charge him, and the case remains unsolved. Merseyside Police still consider the case open.
• Mary Rogers (21–22), also known as the “Beautiful Cigar Girl,” was found dead in the Hudson River on July 28, 1841. Her story became famous 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 December 31, 1843, in Knightsville, Rhode Island. Of the three men tried, only one, John Gordon, was found guilty. He was later cleared of guilt after his death in 2011.
• Joseph Smith (38), founder of the Church of Jesus Christ and Latter Day Saints, and his brother Hyrum Smith (44) were killed on June 27, 1844, when a mob attacked the jail in Carthage, Illinois, where they were being held for treason. Five suspects were tried but found not guilty, and others fled before they could be arrested.
• Françoise de Choiseul-Praslin, wife of French duke Charles de Choiseul-Praslin, died shortly after being beaten and stabbed in her family’s Paris apartment on August 17, 1847. Her husband was arrested but committed suicide during his trial, claiming his innocence. No other suspect was ever identified. The case contributed to the French Revolution of 1848.
• Richard H. Barter (26), a member of a stagecoach robbery gang in California, was found dead outside Auburn on July 12, 1859. He had been injured by law enforcement the day before, but it was unclear who fired the fatal shot.
• Bohlke Luerssen (52), a well-known German immigrant who made syrups and cordials in New York, was found floating in water near Sibyl’s Cave in Hoboken on July 12, 1859. A former employee named John Schuman was suspected of killing him, but no evidence was found to charge him.
• 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 identified.
• John Bozeman (32), an American frontiersman who helped create the Bozeman Trail and founded the city of Bozeman, Montana, was killed along the Yellowstone River on April 20, 1867. The cause of his death is unclear, with theories ranging from an attack by Native Americans to revenge for his actions.
• Sakamoto Ryōma (31) and Nakaoka Shintarō (29), Japanese samurai who worked to end the rule of the Tokugawa shogunate, were killed on December 10, 1867, during an attack at Kyoto’s Ōmiya Inn by pro-shogunate assassins. Nakaoka survived for two days and said the killers spoke the Iyo dialect. The Shinsengumi, a shogunate police force, was blamed, and its leader, Kondō Isami, was executed in 1868. However, another group, the Mimawarigumi, later claimed responsibility. The case remains unsolved.
• George W. Ashburn (53), an American Radical Republican politician in Georgia, was killed by members of the Ku Klux Klan on March 31, 1868. Twenty people were accused of involvement, but political interference led to all suspects being released.
• T. C. Hindman (40), an American politician, was shot through the window of his home in Helena, Arkansas, on September 27, 1868, while he was reading the newspaper with his children.
• Alexander Boyd (35), the county solicitor of Greene County, Alabama, was lynched by the Ku Klux Klan on March 31, 1870.
• Benjamin Nathan (56), a financier who later became a philanthropist, was found beaten to death in his New York City home on July 28, 1870. Several suspects were identified, including his son, but no one was ever charged.
• Juan Prim (56), a Spanish general and statesman, was shot through the window of his carriage on December 18, 1870, and died two days later. In 2012, an autopsy suggested he may have been strangled, but the results were inconclusive.
• Sharon Tyndale (65), a former Illinois Secretary of State, was robbed and shot while walking to a train station in Springfield on April 29, 1871.
• Charles Francis Hall (50) died on November 8, 1871, during the Polaris expedition to the North Pole. Before