Leadership of the Montreal underworld could once more be up for grabs, as longtime Mafia boss Vito Rizzuto, 67, died of natural causes at about 3 a.m. Monday at the Sacre Coeur Hospital.

Hospital officials would not confirm the cause of death but other media reports have asserted that Rizzuto died of pneumonia during chemotherapy treatment for lung cancer. No autopsy will be performed on Rizzuto's body, the Quebec Coroner reported, as the death was of natural causes.

Rizzuto's funeral is expected to be a massive affair, likely to take place Monday at the Church of Notre-Dame-de-la-Défense at the corner of Dante and Henri-Julien.

Rizzuto’s death has sparked speculation that another bloody leadership war could be in the cards. 

A period of relative peace and stability had recently returned to the underworld after a series of underworld slayings, which started  the five-and-a-half years Rizzuto spent in a Colorado prison serving a murder sentence.

The challenge to his leadership claimed the lives of his son Nick Jr. four years ago in NDG and father Nick Sr. three years ago at his home on Antoine-Berthelet Ave.

Several of those believed to have sided against Rizzuto have wound up dead or in prison after Rizzuto's return to Montreal in October 2012, as the Rizzuto faction is believed to have successfully quelled the revolt.

Now observers believe that Rizzuto's death is likely to lead to further conflict.

“Now that he's gone it's going to unleash a lot of unprecedented jockeying for the - for his position, his power his financial empire - it's all going to be played out on the streets across Canada,” said author Adrian Humphreys, who wrote a book about the rise of the Rizzuto family.

Last July Rizzuto bought a lavish home next to the Islemere Golf Club in St. Dorothee Laval for over $400,000 under asking price and there was little indication that his health might have been flagging.

Rizzuto was born February 21, 1946 in Cattolica Eraclea, a small village in Siciliy and came with his family to Canada in 1954.

Rizzuto is survived by wife Giovanna and two children Leonardo Rizzuto and Bettina Rizzuto - both of whom are lawyers and members of the Quebec bar - as well as mother Libertina Rizzuto and sister Maria Renda 

Maria Renda's husband Paolo Renda, who was involved in the family business, was kidnapped on May 20, 2010 and has not been seen since.

Rizzuto's death a "tsunami"

Author and organized crime expert Antonio Nicaso described the news as a possible "tsunami" for the local underworld that could lead to violent conflict. 

“There are two possible scenarios,” he told CTV Montreal. “One is that a conflict may arise simply because there is no one that can easily replace Vito Rizzuto. The second is that the Mafia could change and adapt and have a more horizontal, rather than vertical structure, with a confederation of people rather than a Mafia monarch.”

The new Mafia leadership will have to concentrate on rebuilding damage done by investigations into corruption, he says.

“They should concentrate on restoring the relationships exposed by the Charbonneau Commission, which did more damage to organized crime than any rival organization,” he said.

Nicaso described Rizzuto as, “a man ahead of his time who elevated the Montreal Mafia onto the international stage. He was well respected in Europe and very powerful in North and South America and will be remembered as someone who was able to internationalize the Mafia.”

There had been little sign that Rizzuto was in ill-health and the coroner's decision not to conduct an autopsy is not the right way to go, according to Nicaso.

“I think they should have performed an autopsy just to clear the air about his death,” he said.

A hand in corruption

The Sicilian Rizzuto clan has been making headlines since Vito's father Nick Sr. wrested control of the local underworld from the reigning Calabrian Violi clan in a bloody coup that lasted between 1976-1980. 

Although Rizzuto was known as the local godfather, police were unable to convict him in relation to any of the many misdeeds committed by the mob until recent years.

On January 20, 2004 Rizzuto was arrested at home on charges of taking part in a triple murder in New York City in 1981.

Rizzuto’s long attempts to fight extradition eventually failed and he was sentenced to 10 years in prison after pleading guilty for his involvement in the murder. Rizzuto was armed during the triple murder but did not actually shoot anybody.

Rizzuto's name has recently come up numerous times during Charbonneau Commission testimony, the inquiry into corruption and collusion in Quebec.

RCMP officer Linda Fequiere, who took the stand in Sept. 2012, said Vito Rizzuto forged alliances and acting as a peacemaker to solidify his family’s hold on power in Montreal.

He brokered deals between other organized criminals, including the Calabrian mob, Irish mob and biker gangs, she said.

"Vito Rizzuto worked as a mediator. He was someone who could find solutions when there were problems among different groups," Fequiere said.

Family turmoil

While he was in prison, Rizzuto’s father, son and two close associates were all killed.

His son Nick Jr. was murdered in a brazen day time shooting in Notre-Dame-de-Grace days before Christmas in 2009.

His father, Nicolo Rizzuto Sr., was shot and killed in November 2010 as he prepared to sit down to dinner with his wife and daughter. The elder Rizzuto, 86, was gunned down with a sniper's bullet through the window in his own mansion, near Vito's home.

His father’s death came just months after his brother-in-law Paolo Renda disappeared, vanishing from near his luxury home in north-end Montreal. Family members found his car but no trace of Renda, who has not been heard from since.

In May 2010, Rizzuto’s associate Agostino Cuntrera was gunned down in front of his food-distribution business.

Rebuilding interrupted; what’s next

Some onlookers have speculated that the relative recent peace within the Montreal underworld was a result of a truce, which was struck upon news of Rizzuto’s impending death.

One theory has it that Rizzuto met with rivals in the Dominican Republic in April, who agreed not to challenge his leadership after he revealed that he would be dying soon of cancer.

However, assuming that the Rizzuto clan maintain power, possible aspirants to replace him are said to include Rocco Sollecito, 63, or Francesco Arcadi, 60.

Arcadi is still behind bars, however, serving a 15-year-prison term he was given in 2008.

Domenico Manno, 80, who was released from an American prison one year ago, could be another possible leadership candidate, although it's less likely due to his advanced age. Manno was instrumental in the rise of the Rizzuto clan, as he helped kill then-godfather Paolo Violi on January 22, 1978. (Violi's funeral services were also held at the Madonna Della Fesa Church.) 

Peter Scarcella, who has been a reliable Rizzuto ally in Toronto, is also said to be a candidate for a more important role in the group.

Regardless of the next chapter, observers have noted that Rizzuto defied the odds by dying a natural death.

Former RCMP superintendent Ben Soave, who handled organized crime cases, told CTV Montreal not long before Rizzuto was freed that staying alive would be his top priority upon his release.

He was likely a marked man, Soave continued.

The minute he got out of prison, Rizzuto became the hunter, rather than the hunted and went into rebuilding mode, said CTV Montreal’s Stephane Giroux.

People who were supposed to look after his affairs while he was in jail began dying one by one.

“He wasn’t the very forgiving kind,” said Giroux.

-- with files from The Canadian Press