By 1975, Jimmy Hoffa was a convicted criminal, parolee, and one of America's most notorious men. He had become all of those things by being the President of the International Brotherhood of Teamsters. In that position, he became the most effective labor leader and turned the Teamsters into the biggest force among organized labor. He also was in deep with organized crime, which led him to be investigated and convicted on charges of jury tampering in Tennessee in 1964. This put him in Federal Prison, until President Richard Nixon commuted his sentence and released him in 1971. The commutation was seen as dirty, but part of the condition was Hoffa could not continue in his national labor activities. So Hoffa went back to his Local organization in Detroit, and on July 30, 1975, went to a lunch meeting with two organized crime figures, Anthony Giacolone and Anthony Provenzano. Hoffa was never seen again. Although many theories have been put forward, all seem to say he was murdered that day.