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?

full_context: Document 1: Lucchese crime family New Jersey faction: The Lucchese crime family's New Jersey faction, also known as The Jersey Crew, is a powerful faction within the Lucchese crime family. The faction operates throughout the Northern New Jersey area. During the 1970s into the late 1980s, the faction was led by Anthony Accetturo and his protégé Michael Taccetta. In 1987, Victor Amuso took over the family and began demanding a higher percentage of tribute from the faction. Accetturo refused and a war erupted between the New Jersey faction and the New York faction. This left brothers Michael and Martin Taccetta in charge of the faction as they tried to have Accetturo and his family murdered. In 1993, Accetturo defected and became a government witness. He helped convict Michael and Martin Taccetta. Today the faction is controlled by Ralph Perna.
Document 2: Vito Cascioferro: Vito Cascioferro or Vito Cascio Ferro (January 22, 1862 – September 20, 1943), also known as Don Vito, was a prominent member of the Sicilian Mafia. He also operated for several years in the United States. He is often depicted as the "boss of bosses", although such a position does not exist in the loose structure of Cosa Nostra in Sicily.
Document 3: Lucky Luciano: Charles "Lucky" Luciano ( ; born Salvatore Lucania November 24, 1897 – January 26, 1962) was an Italian-American mobster and crime boss. Luciano is considered the father of modern organized crime in the United States for the establishment of the first Commission. He was also the first official boss of the modern Genovese crime family. He was, along with his associates, instrumental in the development of the National Crime Syndicate.
Document 4: Colombo crime family: The Colombo crime family (pronounced ] ) is the youngest of the "Five Families" that dominates organized crime activities in New York City, United States, within the nationwide criminal organization known as the Mafia (or "Cosa Nostra"). It was during Lucky Luciano's organisation of the American Mafia after the Castellammarese War, and the assassinations of Giuseppe "Joe The Boss" Masseria and Salvatore Maranzano, that the gang run by Joseph Profaci was recognized as the "Profaci crime family"
Document 5: Gambino crime family: The Gambino crime family (pronounced ] ) is one of the "Five Families" that dominates organized crime activities in New York City, United States, within the nationwide criminal phenomenon known as the Mafia (or "Cosa Nostra"). The group, which went through three bosses between 1910 and 1957, is named after Carlo Gambino, boss of the family at the time of the McClellan hearings in 1963, when the structure of organized crime first gained public attention. The group's operations extend from New York and the eastern seaboard to California. Its illicit activities include labor and construction racketeering, gambling, loansharking, extortion, money laundering, prostitution, fraud, hijacking, pier thefts, and fencing.
Document 6: Bernardo Provenzano: Bernardo Provenzano (] ; 31 January 1933 – 13 July 2016) was a member of the Sicilian Mafia ("Cosa Nostra") and was suspected of having been the head of the Corleonesi, a Mafia faction that originated in the town of Corleone, and de facto "capo di tutti capi" (boss of all bosses) of the entire Sicilian Mafia until his arrest in 2006.
Document 7: American Mafia: The American Mafia (commonly shortened to the Mafia or Mob) or Italian-American Mafia, is a highly organized Italian-American criminal society. The organization is often referred to by members as Cosa Nostra (] , "our thing") and by the government as La Cosa Nostra (LCN). The organization's name is derived from the original ""Mafia"" or "Cosa nostra", the Sicilian Mafia, and it originally emerged as an offshoot of the Sicilian Mafia; however, the organization eventually encompassed or absorbed other Italian-American gangsters and Italian-American crime groups (such as the American Camorra) living in the United States and Canada that are not of Sicilian origin. It is often referred to as the Italian Mafia or Italian Mob, though these terms may also apply to the separate yet related organized crime groups in Italy.
Document 8: Sam DeCavalcante: Simone Rizzo "Sam" DeCavalcante (March 3, 1912 – February 7, 1997), known as "Sam the Plumber", was a member of the New Jersey Mafia. Claiming descent from the Italian royal family, DeCavalcante was nicknamed "The Count". The Kefauver hearings later named his crime family the DeCavalcante crime family since he was the boss of the family current to those hearings.
Document 9: The Valachi Papers (book): The Valachi Papers is a biography written by Peter Maas, telling the true story of former mafia member Joe Valachi, a low-ranking member of the New York-based Genovese crime family, who was the first ever government witness coming from the American Mafia itself. His account of his criminal past revealed many previously unknown details of the Mafia. The book was made into a film ("The Valachi Papers"), released in 1972, starring Charles Bronson as Valachi.
Document 10: Sam Giancana: Salvatore "Mooney Sam" Giancana (born Salvatore Giangana; June 15, 1908 – June 19, 1975), better known as Sam Giancana, was a Sicilian American mobster, notable for being boss of the Chicago Outfit from 1957–1966. Among his other nicknames were, "Momo", "Sam the Cigar," and "Sammy."
Document 11: Valachi hearings: 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.
Document 12: Joseph Valachi: 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".
Document 13: Luciano Leggio: Luciano Leggio (] ; 6 January 1925 – 15 November 1993) was an Italian criminal and leading figure of the Sicilian Mafia. He was the head of the Corleonesi, the Mafia faction that originated in the town of Corleone. He's universally known with the surname Liggio, a result of a misspelling in court documents in the 1960s.
Document 14: Mafia Commission Trial: The Mafia Commission Trial (February 25, 1985 – November 19, 1986), officially known as United States v. Anthony Salerno, et al., was a criminal trial in New York City, United States. Using evidence obtained by the Federal Bureau of Investigation, eleven organized crime figures, including the heads of New York's so-called "Five Families," were indicted by United States Attorney Rudolph Giuliani under the Racketeer Influenced and Corrupt Organizations Act (RICO) on charges including extortion, labor racketeering, and murder for hire. The case struck a blow against "The Commission," a loose organization of the New York Mafia organizations that met to resolve disputes or discuss criminal activities, sometimes likened to organized crime's board of directors. "Time" magazine called this "Case of Cases" possibly "the most significant assault on the infrastructure of organized crime since the high command of the Chicago Mafia was swept away in 1943," and quoted Giuliani's stated intention: "Our approach... is to wipe out the five families."
Document 15: Joseph Glimco: Joseph Paul Glimco (January 14, 1909 – April 28, 1991) was an Italian American labor leader and well-known organized crime figure based in Chicago, Illinois. He was considered "Chicago's top labor racketeer" in the 1950s. One high-ranking Chicago Teamsters leader noted in 1954, "He is the mob. When he opens his mouth, it's the syndicate talking." Glimco was active in the International Brotherhood of Teamsters (IBT) and a close associate of Teamsters president Jimmy Hoffa. He was a capo in the Chicago Outfit, an organized crime syndicate, and oversaw the syndicate's labor racketeering efforts. He worked closely with Tony "Joe Batters" Accardo, who led the Chicago Outfit from 1943 to 1957, and Sam "Momo" Giancana, who led the syndicate from 1957 to 1966. A United States Senate committee once claimed that Glimco ran "the nation's most corrupt union."
ground_truth: Joseph Michael "Joe Cargo" Valachi