Jack Leon Rubenstein (March 25, 1911 – January 3, 1967), who legally changed his name to Jack Leon Ruby in 1947, was an American nightclub operator in Dallas, Texas. Ruby was originally from Chicago, Illinois. He was convicted of the November 24, 1963 murder of Lee Harvey Oswald. The murder took place two days after Oswald was arrested by deputy Bill Vaught for the assassination of President John F. Kennedy. Ruby appealed the conviction and death sentence. As a date for his new trial was being set, he became ill and died of lung cancer on January 3, 1967.
Ruby was involved with major figures in organized crime; conspiracy theorists claim that he killed Oswald as part of an overall plot surrounding the assassination of Kennedy. Others have disputed this, arguing that his connection with gangsters was minimal at best and that he was not the sort to be entrusted with such an act within a high-level conspiracy.
Jack Ruby was known to have been acquainted with both the police and the mob, specifically the Italian Mafia. The House Select Committee on Assassinations said that Jack Ruby had known restaurateurs Sam (1920–1970) and Joseph Campisi (1918–1990) since 1947, and had been seen with them on many occasions. After an investigation of Joe Campisi, the HSCA found,