Question: The Valachi hearings, also known as the McClellan hearings, investigated organized crime activities across America, the hearings were named after which American gangster, notable as the first member of the Italian-American Mafia to publicly acknowledge its existence,was a major government witness against the American Mafia?

Related documents: [0]  [DOC] The Valachi hearings, also known as the McClellan hearings, investigated organized crime activities across America and investigated leading mafia figures of the era such as Sam Giancana of Chicago. The hearings were initiated by Arkansas Senator John L. McClellan in 1963. The hearings were named after the major government witness against the American Mafia, Joseph Valachi. [END] 
[1]  [DOC] Joseph Michael "Joe Cargo" Valachi (September 22, 1904 – April 3, 1971) was an American gangster, notable as the first member of the Italian-American Mafia to publicly acknowledge its existence, and credited with popularization of the term "Cosa Nostra". [END]  
Answer: Joseph Michael "Joe Cargo" Valachi
Joseph Michael "Joe Cargo" Valachi