In November 1963, two days after shooting President John F. Kennedy, Lee Harvey Oswald was fatally shot by Jack Ruby in the basement of Dallas Police Headquarters.

In September 1964, the Warren Commission came to the controversial conclusion that Oswald had acted alone when assassinating Kennedy. Although controversial, the conclusion was supported by investigations from the Dallas Police Department, the Federal Bureau of Investigation , the United States Secret Service, and the House Select Committee on Assassinations.

Source: Wikipedia