Quebec police have made five arrests in connection to the slaying of a mob boss who once ran a New York City crime family.

Salvatore Montagna, who U.S. authorities said once led the notorious Bonnano crime family, was shot dead near a Montreal river last month.

Among those arrested was Raynald Desjardins, a prominent figure in Montreal with links to the Rizzuto family.

Desjardins, 59, and four others face first-degree murder charges.

"We believe we have just dealt a major blow to organized crime, particularly Italian organized crime," Insp. Roberto Bergeron told a news conference on Tuesday.

Montagna's slaying was the latest in a series of killings that have shaken up organized crime in Quebec.

Two of those arrested were Vittorio Mirarchi, 34, and Felice Racaniello, 27. Police did not release the other two names.

Vito Rizzuto, the alleged head of the Montreal mob, is currently jailed in the United States. A series of murders and disappearances in 2009 and 2010 has seriously reduced the strength of his organization.

With files from The Canadian Press