They had to stay in shape, Gotti reportedly said, because once they got out, he was going to retake control of the Gambino enterprise.

This week, that exchange took on new significance. Late Wednesday, the acting boss of the Gambino crime family, Francesco Cali, was shot dead outside his Staten Island home, just six months after Gotti had been released from federal custody.

Police commanders said Thursday that it was too early in the investigation to determine if Cali’s killing was related to Gotti’s release, or was mob-related at all. But one avenue of investigation remains the possibility of an internal war among family associates, former law enforcement officials said.

Cali represented a new chapter in the Gambino family’s history. He was part of a Sicilian faction that took over the family in 2011, when Domenico Cefalù rose to be the acting boss. Both Cefalù and Cali had tapped networks in Palermo, Sicily, for foot soldiers, and they adopted a quieter approach to their business dealings.

Gene Gotti, 72, represented the old guard. He is the younger brother of John J. Gotti, the infamous “Dapper Don” who ran the family until his conviction on murder and racketeering charges in 1992. John Gotti died behind bars a decade later.

A third brother, Peter Gotti, who investigators say became the family’s boss after John Gotti’s death, is serving a life sentence in prison.

Given the era of relative peace among New York’s five major Mafia families, many experts on organized crime have begun theorizing that the killing of Cali might point to a struggle within the family.

If so, it could signal a bloody new chapter for the enterprise, where a rift has festered between the Sicilian leadership of Cali and Gotti loyalists.

“What happened here? I don’t know,” said James Hunt, the former head of the Drug Enforcement Administration office in New York, where he handled the Gambino portfolio. “You’ve got guys recently released. Gene Gotti was recently released. He may think he was the heir to the throne.”

Cali, 53, was drawn out of his house at 9:17 p.m. Wednesday when a pickup truck rammed repeatedly into his Cadillac SUV, which was parked on the street in front of his home.

Security camera video from the Cali house — obtained through a search warrant because the family was not cooperating — showed Cali coming outside and interacting with the truck’s driver, who seconds later pulled out a pistol, police said. The gunman shot Cali six times before speeding off.

Chief Dermot Shea, who runs the Police Department’s detective bureau, would not say whether investigators had spoken to Gene Gotti as of Thursday afternoon.

When Gene Gotti was arrested in the late 1980s, his brother’s enterprise was starting to crumble. The Gambinos’ heroin business was being undersold by the Colombian and Mexican cartels, who could move drug shipments cheaper and faster. And federal investigators were circling.

Gene Gotti was convicted on a heroin-trafficking charge in 1989 and was sentenced to 59 years in federal prison. At the time, he was reputed to be a Gambino captain, officials said.

John Gotti, who eluded convictions in three trials, was finally arrested by the FBI in 1992 and convicted of racketeering, extortion and murder. He was foiled after his underboss, Salvatore Gravano, decided to cooperate with the government.

In recent years, Cali emerged as the heir apparent to a new Gambino generation, becoming the acting boss in 2015, prosecutors said. He was a protégé of Cefalu, and the pair spent the last decade quietly overhauling much of what John Gotti had built, opting for a quiet, reserved approach to organized crime.

“They’ve gone back to the old ways, staying under the radar, no flash,” Hunt, the former DEA head, said. “They got so sick of all the bad stuff from Gotti that they really pulled it in.”

Cali in particular maintained close ties to the Mafia in Sicily, where he had ties through blood and marriage. He filled the family’s decimated ranks with Sicilians, known to be far less flamboyant and showy than their American associates. He quietly cultivated the family’s hold in New York City’s construction and trucking industries, and pulled the clan back under the radar.

Rarely seen in public, Cali avoided the spotlight John Gotti had once sought. He caught only one federal charge — on a racketeering scheme involving the failed construction of a NASCAR speedway in Staten Island — and spent less than two years in jail.

Cali’s shooting is the highest-profile Mafia killing in more than three decades. In 1985, Gambino boss Paul Castellano was shot in broad daylight outside Spark’s Steak House in midtown Manhattan. The hit, authorities said, had been sanctioned by John Gotti, who took control of the clan not long after.

For investigators who have long watched the Gambinos, Cali’s slaying was so brazen that it raised the possibility it was a personal vendetta. Mafia assassinations are usually carried out by a team of gunmen in a place far from the target’s home and family — a restaurant, a barber shop, a cafe. The assassins also generally take care to avoid security cameras and use cars and guns that are difficult to trace.

“This is not how usually the mob operates, especially not with a person at this high level,” said Robert Boyce, a former chief of the Police Department’s detective bureau. “That is the primary question, is this a sanctioned hit?”

Killings this high profile, Boyce said, rarely go unanswered.

“There’s a very good probability there will be more violence,” he said.