JOLIETTE, Que. - First-degree murder charges have been laid against four people in the slaying of a onetime U.S. Mafia boss believed to be involved in Montreal's bloody underworld leadership battle.

Salvatore Montagna, a former head of New York's notorious Bonanno crime family, was gunned down as he fled a home and was found by a river last November.

Raynald Desjardins, who once had close ties with jailed Montreal Mob boss Vito Rizzuto, was among three men formally charged with first-degree murder and conspiracy to commit murder this morning.

Desjardins was charged today along with two other men today, Vittorio Mirarchi and Felice Racaniello, under heavy security at a courthouse north of Montreal.

A fourth man who owned the house, Jack Simpson, is currently incarcerated in Ontario after having his parole revoked and will be arraigned on the same charges at a later date.

Two other men also arrested on Tuesday are facing numerous weapons-related charges.

The charges filed seem to indicate that the conspiracy began within days of an attempt on Desjardins' own life in September.

A bitter and bloody struggle has ensued since Rizzuto was jailed in the United States, one that has claimed the lives of many of his closest family and friends.

The accused return to court on Jan. 4.