Jack Leon Ruby was an American nightclub owner notable for murdering Lee Harvey Oswald.
Born in Chicago, Ruby operated nightclubs in Texas. On November 24, 1963, two days after the assassination of John F. Kennedy in Dallas, Ruby shot and mortally wounded Oswald in Dallas Police Headquarters and was immediately arrested. The shooting happened on live television. Ruby was convicted and sentenced to death. The conviction was overturned on appeal, and he was granted a new trial, but Ruby fell ill, was diagnosed with cancer, and died of a pulmonary embolism on January 3, 1967.
In 1964, the Warren Commission concluded that there was no evidence Ruby was part of a conspiracy; despite this, Ruby's murder of Oswald has stoked John F. Kennedy assassination conspiracy theories.