This is a list of people who disappeared mysteriously from 1910–1970 or whose deaths or exact circumstances thereof are not substantiated. Many people who disappear end up declared presumed dead and some of these people were possibly subjected to forced disappearance.
This list is a general catch-all; for specialty lists, see Lists of people who disappeared.
1910s DatePerson(s)AgeMissing fromCircumstances 1910Burt Alvord42–43Central AmericaAn American lawman-turned-outlaw, Alvord had been a Cochise County, Arizona, deputy, but had turned to crime—primarily train robbery—by the early 1900s. He was last seen in 1910 working as a Panama Canal employee. Alvord's ultimate fate is unknown. 12 July 1910Alexander Pfitzner29Marblehead, Massachusetts, U.S.Hungarian-American engineer and aviation pioneer who designed and flew the first monoplane to be built in the United States. Reported as suicidal due to his lack of commercial success, Pfitzner is said to have died by suicide in Marblehead Harbor on 12 July 1910. His body was never found, and there were rumoured sightings of him in New York City in September.12 December 1910Dorothy Arnold25New York City, New York, U.S.Manhattan socialite and perfume heiress Dorothy Arnold vanished after buying a book in New York City. She intended to walk through Central Park, but was never seen again.27 August 1911Modesta Cefai 6Rabat, Gozo, MaltaSix-year-old Modesta Cefai disappeared from Rabat, Gozo, after she wandered out of her house. March 1912Sebastiano DiGaetano~50New York City, New York, U.S.DiGaetano disappeared shortly after stepping down as boss of the Maranzano crime family. It is believed that he and his wife returned to Italy, but this theory is unconfirmed.23 August 1912Bobby Dunbar4St. Landry Parish, Louisiana, U.S.Bobby Dunbar disappeared during a fishing trip. A child found in the custody of William Cantwell Walters of Mississippi eight months later was ruled to be Bobby Dunbar by a court-appointed arbiter, and Walters was found guilty of kidnapping. The child grew up as Bobby Dunbar, had four children of his own, and died in 1966. In 2004, DNA tests proved that the child found was not related to Bobby's brother, Alonzo.DNA clears man of 1914 kidnapping conviction USA Today 2004-05-05, Allen G. Breed (Associated Press).December 1913Ambrose Bierce71Chihuahua, MexicoThe American writer known for An Occurrence at Owl Creek Bridge and The Devil's Dictionary was supposedly last heard from in a letter of December 1913 to his secretary and companion, Carrie Christiansen. Theories of his demise are plentiful; some claim that he perished in war-torn Mexico or perhaps was executed as a spy in the municipal cemetery of Sierra Mojada, Coahuila, where a gravestone bearing his name was erected in 2004. Professional American skeptic Joe Nickell, however, has concluded that Bierce deliberately misled the public about his destination, and that Bierce actually went to the Grand Canyon where he died by suicide.The Death of Bierce Ambrose Bierce Appreciation Society.Ambrose Bierce, "the Old Gringo": Fact, Fiction and Fantasy Glenn Willeford.Retired priest erects Bierce gravestone in Sierra Mojada, Mexico The Ambrose Bierce Site James Lienert, Don Swaim.16 January 1914F. Lewis Clark52Santa Barbara, California, U.S.Clark, a prominent industrialist from the U.S. state of Idaho, disappeared on a business trip to Santa Barbara, California. March 191424ChileA lieutenant in the Chilean Army, Bello disappeared during a qualifying examination flight over central Chile. At some point during the flight, Bello became lost in the clouds and was never seen again. Although search efforts commenced within hours, neither he nor his aircraft were ever found.September 1914František Gellner33Zamość, Austrian Galicia, Austria-HungaryThe Czech poet, short-story writer, artist and anarchist was reported missing on 13 September 1914.Lexikon české literatury, vol.I, Academia, Praha 2000, pp.795–797, and Slovník českých spisovatelů, Československý spisovatel, Praha 1964, p.112.25 January 1915Arthur Lang24Cuinchy, FranceThe English first-class cricketer and serviceman of the Grenadier Guards was reported missing in action on 25 January 1915 during the First World War, presumably killed.12 August 1915Frank Beck54Gallipoli, TurkeyA land agent for the British royal family and volunteer leader of a company, Beck and many of his men went missing during the Gallipoli campaign. His body was never identified.February 1916David M. Kelly75Boston, Massachusetts, U.S.Kelly, an American lawyer, politician, and Civil War veteran who was earlier in his life the 29th speaker of the Wisconsin State Assembly, was last seen at his law office in Boston. He was thought to be taking a train to his residence in Sharon, Massachusetts. He was never found, despite an intensive search by hired detectives.18 July 1916Eric Milroy28Delville Wood, FranceMilroy, a rugby union player who represented Scotland and Watsonians, was commissioned in the Black Watch at the start of World War I, but went missing on 18 July 1916, presumably killed. According to his great nephew, Milroy's mother never believed he was dead, and left the lights on in the house at night should he ever return.8 August 1916Oscar Linkson28Guillemont, FranceLinkson, an English footballer, enlisted in the 1st Football Battalion to fight in France. He went missing in a battle to seize Guillemont Station during the Battle of the Somme. His body was never found.14 September 1916Luigi Forlano32Villanova, Austrian Littoral, Austria-HungaryForlano, an Italian footballer and founding partner of the Juventus Football Club, fought as captain of the Bersaglieri during the First World War. He went missing in Villanova (today Nova Vas nad Dragonjo, Slovenia) while combating Austrian forces, and his remains were never recovered.28 July 1917Ellis Vair Reid27Ypres, BelgiumA Canadian RAF World War I flying ace credited with 19 victories, Reid's aircraft disappeared over Ypres while flying with the No. 10 (Naval) Squadron. His remains were never found.11 September 1917Georges Guynemer22Poelcappelle, BelgiumGeorges Guynemer was a French World War I flying ace who mysteriously disappeared on 11 September 1917 in Poelcappelle, Belgium. Reported missing in action on failing to return from a combat flying mission, Guynemer was never seen or heard from again.27 October 1917Arthur Rhys-Davids20Roeselare, West Flanders, BelgiumA British flying ace and veteran of the Third Battle of Ypres, Rhys-Davids was reported missing in action on 27 October 1917. His aircraft was last seen over the Belgian city of Roeselare.27 May 1918William Fiske32Aisne, FranceEnglish professional football goalkeeper and a sergeant in the Border Regiment, Fiske went missing during the Third Battle of the Aisne. His remains were never recovered.27 May 1918Rudolf Windisch21Gouvrelles, FranceWorld War I flying ace Windisch was reportedly captured as a prisoner of war in a French prison. Reports differed on his status, with some rumors claiming that he died in captivity. He was never seen again and his true fate is unknown.June 1918Knud Andersen51EnglandDanish zoologist Knud Andersen mysteriously disappeared in June 1918. His colleague Oldfield Thomas submitted his final manuscript on his behalf, stating that Andersen expected "to be absent from his scientific work for some time."5 June 1918Charles Quette23FranceQuette, a French World War I flying ace credited with ten confirmed and five unconfirmed aerial victories, disappeared five days after being temporarily promoted to sous lieutenant.28 July 1918Antoine Cordonnier26FranceCordonnier, a French World War I flying ace credited with five aerial victories, disappeared six months after transferring to Escadrille 15.Over the Front: A Complete Record of the Fighter Aces and Units of the United States and French Air Services, 1914–1918 Norman Franks, Frank W. Bailey. Grub Street, 1992. , 14 August 1918Herbert Gould26Douai, FranceGould was a British World War I flying ace credited with six aerial victories. He and his gunner/observer, Second Lieutenant Ewart William Frederick Jinman, were reported missing in action near Douai, France, on 14 August 1918.3 September 1918Arnaldo Berni24Punta San Matteo, County of Tyrol, Austria-HungaryBerni, a Royal Italian Army soldier noted for using his mountaineering skills to repel the Austro-Hungarian Army, was declared missing in action during the Battle of San Matteo.2 June 1919Mansell Richard James25Tyringham, Massachusetts, U.S.Canadian flying ace James was last seen in western Massachusetts on 2 June, just days after a record-setting flight between Atlantic City and Boston.2 December 1919Ambrose Small56Toronto, CanadaThe Canadian millionaire disappeared from his office. He was last seen at 5:30 pm on 2 December 1919 at the Grand Opera House.
1920s