Italy’s most wanted Cosa Nostra Mafia boss has finally been captured.

Matteo Messina Denaro, nicknamed “Diabolik” and “‘U Siccu” (Skinny One), was arrested by Italian law enforcement at a private hospital in Sicily on Monday, which he was reportedly visiting under a false name to receive chemotherapy, according to Reuters.

Denaro allegedly spent the last 30 years in hiding after being convicted and sentenced to life in prison in absentia for multiple homicides. He had once boasted that he had “filled a cemetery” by himself, according to The Guardian.

“Making connections with business, and in some cases, politics, has always been in the DNA of [the Mafia],” said Nino di Matteo, a former anti-Mafia prosecutor in Palermo. “I believe Matteo Messina Denaro knows a lot about those connections, and it would be a great step forward if he decided to collaborate with justice, and tell the truth about what he knows.”

Denaro’s alleged crimes include the 1993 bombing attacks in Milan, Florence, and Rome; the kidnapping, torture, and killing of an 11-year-old boy, who was the son of a mafioso who had turned state’s witness; and the murders of anti-Mafia prosecutors Giovanni Falcone and Paolo Borsellino in 1992.

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Like many other mafiosos in Italy, the career criminal built his wealth by infiltrating local government to control state contracts in the construction, energy, and carting industries, using violence whenever necessary to maintain that control.

Denaro’s arrest follows the 30th anniversary of the arrest of notorious Mafia boss Salvatore “The Beast” Riina, who passed away in 2017.

Criminology expert Anna Sergi of the University of Essex told the BBC that Denaro “represents the last fugitive the Italian state really wanted to get its hands on.”

“The secrets he is said to keep fuel conspiracies around mafia-state agreements in the 1990s,” Sergi said. “He is the essence of the great historical power of Cosa Nostra. The myths around his period on the run are part of the reason why the Mafia myth endures.”

According to The Guardian, Denaro had been able to hide for so long because many people in Sicily who lived in his territory exhibited a degree of loyalty to the fugitive.

“If you asked, where is Matteo Messina Denaro, people would say, he’s either dead, or he’s in the province of Trapani,” said Giacomo di Girolamo, one of Denaro’s biographers.

Italian President Sergio Mattarella congratulated the minister of the interior and the Italian military police for their capture of the Mafia boss. Mattarella’s own brother, Piersanti, was killed by the Mafia in 1980.

Despite the high-profile arrest, other officials caution that Denaro being put behind bars is not a knockout blow to organized crime in Italy.

“Obviously the mafia has not been defeated, and it would be a mistake to think it so,” said Palermo prosecutor general Maurizio De Lucia.

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