High Quality Content by WIKIPEDIA articles! Giovanni Ignazio Dioguardi, also known as "John Dioguardi" and "Johnny Dio" (April 29, 1914 – January 12, 1979), was an Italian-American organized crime figure and a labor racketeer. He is known for being involved in the acid attack which led to the blinding of newspaper columnist Victor Riesel, and for his role in creating fake labor union locals to help Jimmy Hoffa become General President of the Teamsters.