Francis P. "Cadillac" Salemme in 1995. (FBI/AP)

He was already behind bars. But the victory for prosecutors, if it can be called that, was ensuring the old man would die there.

Frank “Cadillac” Salemme, a former Mafia boss in New England, has a reputation (and a criminal record) that is shocking and cinematic, even for a bad man often surrounded by other bad men. A car bombing that tore a lawyer’s leg off. Stints in prison for racketeering charges and perjury. Extortion. Multiple murders.

In June, he picked up one more — murder of a federal witness. Salemme, along with co-defendant Paul Weadik, was convicted of killing a nightclub owner, Steve DiSarro, to keep investigators from finding out about his hidden ties to the business. On Thursday, Salemme, 84, and Weadik, 63, were both given the mandatory sentence — life in prison.

The sentencing marked the conclusion of a decades-long slog to bring down the last of the big-name mafia kingpins, and prosecutors made it clear they are relieved to be finished. U.S. Attorney Andrew Lelling called the case “the end of a long, dark chapter” in Boston history.

The beginning of the end came in March 2016, when authorities started digging behind an old mill in Providence, R.I. Initially, they’d come for the 1,400 marijuana plants growing there. But the building’s owner, William Ricci — a man with ties to the mob, according to reporting from the Providence Journal — tried to bargain, telling them the real scandal was deep beneath the dirt. It took two days of digging to uncover bones and shreds of a track suit, remains that were eventually confirmed to be those of DiSarro, the nightclub owner.

When the bones were found, Salemme was living in Atlanta under the name “Richard Parker” as part of the FBI’s Witness Protection Program, the Boston Globe reported. Salemme fled to Connecticut, where authorities who arrested him found $28,000 in cash stashed throughout his hotel room.

At his sentencing, the graying former capo insisted on his innocence, jumping to his feet to accuse the victim’s family of lying, the Associated Press reported.

“The real story about what happened here has not been out yet,” Salemme said. “But it will come out. It will come out in time.”

The truth, as prosecutors and the jury agreed, was that Salemme needed DiSarro silenced, so in May 1993 he stood by as his son, Frank Salemme Jr., strangled DiSarro, while Weadik held his feet. Salemme Jr. died in 1995.

One of the key witnesses in the five-week trial was another mobster, Stephen “The Rifleman” Flemmi, the former right-hand man of Whitey Bulger. Flemmi described how he swung by Salemme’s house and walked in on the murder. He and Salemme had been buddies since the 1960s, but their friendship disintegrated under the pressure of prosecution. Flemmi is currently serving a life sentence for the murders of 10 people, and his testimony was just the latest in a string of times the two men had turned on each other.

Later in the trial, two brothers, former Rhode Island mobsters Joseph and Robert “Bobby the Cigar” DeLuca, testified that they’d helped bury DiSarro behind the old mill after Salemme had brought the body to Providence himself.

Still, Salemme’s attorney, Steve Boozang, tried to portray the men who turned against Salemme as liars throughout the trial and to paint the killing as a rare exception — a death in Salemme’s orbit that the man hadn’t had a hand in.

“It was a little bit of kill or be killed back then,” Boozang said during the trial, the New York Times reported. “Just because he’s done these bad things doesn’t mean he’s done this.”

At the sentencing, DiSarro’s children sought to emphasize the real, human cost of organized crime.

“This is not a movie. This is our life,” Colby, one of DiSarro’s daughters, told the court.

DiSarro’s son, Michael, said he hoped Salemme would spend the rest of his days sitting in a cell, thinking about the kids he’d forced to grow up without a father.

Assistant U.S. Attorney Fred Wyshak, who has been fighting to bring down Boston mobsters since 1989, choked up when he described some of Salemme’s crimes, according to reporting from the Providence Journal.

“It grieves me that it’s taken this long to put him away for the rest of his life, because he richly deserves that,” Wyshak said.

The sentencing marked the end of the line for Salemme, and with it, perhaps the end of the blockbuster mobsters. Mob activity today is not the stuff of “The Sopranos,” prosecutors said, and no one says “bada-bing” (although one witness, Thomas Hillary, uttered it during Salemme’s trial, the New York Times reported).

DiSarro’s nightclub is long gone now. Soon, the ground where it was located will house a headquarters for General Electric.