Question: Nicholas Scibetta's hit man brother-in-law, who confessed to being involved in the murder of 19 people, helped prosecutors convict what Gambino family boss?

Context:
Anthony Casso
Anthony Salvatore "Gaspipe" Casso (born May 21, 1940 in Brooklyn, New York City) is an Italian-American mobster and former underboss of the Lucchese crime family.
 During his career in organized crime, Casso was regarded as a "homicidal maniac" in the American Mafia, single-handedly killing over 40 to 50 people, and ordering as many as 100 or more murders.
 Former Lucchese captain and government witness Anthony Accetturo once said of Casso, "all he wanted to do is kill, kill, get what you can, even if you didn't earn it."
 In interviews and on the witness stand, Casso has confessed involvement in the murders of Frank DeCicco, Roy DeMeo, and Vladimir Reznikov.
 Casso has also admitted to several attempts to murder Gambino family boss John Gotti.
Aniello Dellacroce
Aniello John "Neil" Dellacroce (March 15, 1914 – December 2, 1985), also known as "Mr. Neil," "Father O'Neil" and "The Tall Guy", was an Italian-American gangster and underboss of the Gambino crime family.
 He rose to the position of underboss when Carlo Gambino moved Joseph Biondo aside.
 Dellacroce was a mentor to Gambino crime family boss John Gotti.
1990 in organized crime
December 11, 1990, the FBI arrests Gambino Family boss John Gotti, underboss Salvatore "Sammy the Bull" Gravano and consigliere Frankie Locasio on racketeering charges.
Edward J. O'Hare
Edward Joseph O'Hare, aka "Easy Eddie" (September 5, 1893 – November 8, 1939), was a lawyer in St. Louis and later in Chicago, where he began working with Al Capone, and later helped federal prosecutors convict Capone of tax evasion.
 In 1939, a week before Capone was released from Alcatraz, O'Hare was shot to death while driving.
 He was the father of Medal of Honor recipient Butch O'Hare, for whom Chicago O'Hare Airport is named.
Yema stabbings
Yang Qingpei (born 1989 ) is a Chinese man accused of the mass murder of 19 people.
 He confessed to killing his parents in an argument over money and then killing 17 neighbours in an attempt to cover up his crime on September 29, 2016, state media reported.
 The youngest victim of the murderous rampage in a remote village in southwest China was three, the oldest 72.
 They were members of six families.
 Suspect Yang Qingpei, aged 28, went to his home village of Yema on Wednesday.
 He was arrested in Kunming, capital of Yunnan Province, on Thursday.
 The Xinhua state news agency report did not say how the villagers were killed.
 Mass killings are rare in China and access to firearms is tightly controlled.
 The crime took place in Qujing, Yunnan Province.
Joseph Iannuzzi
Joseph Iannuzzi, Jr., (1930 or 1931 – September 20, 2015), also known as "Joe Dogs", "Joe Diner" and "Joe Drywall", was a Gambino crime family associate and FBI informant whose cooperation influenced events surrounding the late 1985 assassination of Gambino family boss Paul Castellano and played an indirect, but valuable, role in the 1985 Mafia Commission Trial.
 Iannuzzi is the author of several books: "The Mafia Cookbook", "Cooking on the Lam", and his autobiography "Joe Dogs: The Life and Crimes of a Mobster".
 Iannuzzi died September 20, 2015, in Kerrville, Texas, at the Veterans Administrations Medical Center.
 He is survived by his seven children, seven grandchildren and six great grandchildren.
Confessions of an Economic Hit Man
Confessions of an Economic Hit Man is a partly autobiographical book written by John Perkins published in 2004.
 It provides Perkins' account of his career with engineering consulting firm Chas.
 T. Main in Boston.
 According to Perkins, his role at Main was to convince leaders of underdeveloped countries to accept substantial development loans for large construction and engineering projects that would primarily help the richest families and local elites, rather than the poor, while making sure that these projects were contracted to U.S. companies.
 Later these loans would give the U.S. political influence and access to natural resources for U.S. companies.
 He refers to this as an "economic hit man."
 Although he states that throughout his career he has always worked for private companies, and suggests a system of corporatocracy and greed, rather than a single conspiracy, he claims the involvement of the National Security Agency (NSA), with whom he had interviewed for a job before joining Main.
 According to the author, this interview effectively constituted an independent screening which led to his subsequent hiring as an economic hit man by Einar Greve, a vice president of the firm (and alleged NSA liaison).
Donald Lavoie
Donald Lavoie (born 21 May 1942) is a self-proclaimed former hit man for the Dubois Gang, situated in Montreal, Quebec, Canada.
 During his career as a hit man, Lavoie assassinated at least 15 people, to which he later confessed.
 Lavoie's testimony was used by the Montreal Police Force to convict members of the Dubois Gang.
 Until his testimony, the Dubois Gang had been nearly impossible to infiltrate.
Sammy Gravano
Salvatore "Sammy the Bull" Gravano (born March 12, 1945) is a former underboss of the Gambino crime family.
 He is known as the man who helped bring down John Gotti, the family's boss, by agreeing to testify against him and other mobsters in a deal in which he confessed to involvement in 19 murders.
Nicholas Scibetta
Nicholas Scibetta, also known as "Little Nicky" (died 1978), was a Sicilian American mobster who was the nephew of Joseph and John Zicarelli, the brother-in-law of Sammy Gravano and uncle of mafioso Gerard Gravano, who was a Gambino crime family mob associate who was later marked as a stool pigeon by fellow crime family members.

Answer: John Gotti