As soon as Genovese capo Ralph Coppola disappeared in September 1998, gangbusting FBI agents knew that a mob moratorium on murder that had begun five years earlier was over. They also knew the most likely suspect in the rubout was behind bars.

Nearly six years and thousands of tape-recorded conversations later, the FBI finally got the evidence it needed to obtain an indictment charging a onetime acting boss, Liborio “Barney” Bellomo, with Coppola’s murder.

The breakthrough, according to a secret FBI affidavit obtained by Gang Land, came on July 31, 2004, when a long-time mob lawyer-crime family messenger, Peter Peluso, detailed Bellomo’s alleged role in the slaying during a quiet talk he was having with a veteran Genovese capo, John “Buster” Ardito.

During the discussion, FBI agent William Inzerillo wrote, Peluso told how Barney — who had sponsored Coppola’s induction and later promoted him — had authorized family leaders to whack his former protégé during a jailhouse conversation he had with Bellomo a few days before the murder.

Peluso gave the feds what they previously lacked, a witness to the murder conspiracy. As a result, Bellomo, 49, was tagged with the slaying early this year. But the evidence of his connection to Coppola’s murder, Gang Land has learned, was the outgrowth of a bizarre mistaken identity case that began a year before the killing of Coppola, whose body has never been found.

The unwitting catalyst for Bellomo’s involvement in the slaying, according to court records and knowledgeable sources, was a young man named Daniel Provenzano, a nephew of the late Genovese capo Anthony “Tony Pro” Provenzano, someone Bellomo insists he never met.

The younger Provenzano fancies himself a movie-maker. In fact, he wrote, directed, and produced a fairly unmemorable 2003 movie about mob life called “This Thing of Ours.” The film starred Provenzano as a modern-day hood who uses computer skills to try to become a “made man.” The movie co-stars “Sopranos” wiseguy-actors Vincent Pastore and Frank Vincent, and features James Caan, of “The Godfather” fame, in a cameo role.

Bellomo’s Provenzano-related problems began several years before the movie, when Provenzano was arrested on June 12, 1997, by a New Jersey state and federal task force and accused of trying to extort half an insurance company from its owner for a $40,000 gambling debt.

Before his arrest, Provenzano had been tape-recorded telling his victim that his mob superior, Barney Bellomo, was a “stone-cold killer” with a dozen hits on his resume and that Bellomo had demanded a $100,000 tribute from the insurance executive.

The following April, the New Jersey attorney general’s office subpoenaed Bellomo, who was then in a federal prison in Atlanta serving time for a 1996 New York extortion case, to appear before a state grand jury investigating Provenzano’s activities.

Barney was not pleased. Not only was the Mercer County prison a virtual hellhole compared to his digs in Atlanta — he was locked down 22 to 23 hours a day, he claimed — but he was the wrong Liborio “Barney” Bellomo.

How many Liborio Bellomos with the nickname Barney could there be? As it happens, there are at least two, according to affidavits submitted by the former acting boss, and Liborio Thomas Bellomo, a cousin who is a reputed Genovese family associate.

They are often mistaken for each other, with good reason. Their fathers are brothers, who, to make matters even more baffling, married a pair of sisters.

In court papers supporting his cousin, Liborio Thomas wrote that the two were often confused. Strangers “would incorrectly attribute to me things that were meant for my cousin,” he wrote, “or they would attribute to my cousin, things that were meant for me.”

More important, Liborio Thomas, who is two years older than his cousin, was sure he was the Barney Bellomo whom authorities wanted to question. He had worked for a Provenzano printing company for 11 months and was present at a meeting Provenzano had with his alleged victim the previous year.

The Bellomos’ complaints fell on deaf ears, however. On successive days, state and federal judges rejected their arguments, and Barney — that is, the acting boss Barney — was granted immunity and ordered to testify or face criminal contempt charges.

Meanwhile, the case against Danny Provenzano dragged on until November 2002, when on the eve of trial, he copped a plea deal and began serving a 10-year prison term the following year, just as “This Thing of Ours” was being released.

It was while the jailed Bellomo was trying to extricate himself from New Jersey that Peluso went to visit his client at the Garden State holding facility. It was there, Peluso has told the feds, that Barney okayed the hit on Coppola, according to court records.

As further proof of Bellomo’s involvement, Mr. Inzerillo, the FBI agent, quoted an apparently relaxed talk overheard on an FBI bug between Peluso and Ardito two years ago on a Saturday afternoon in Mario’s restaurant on Arthur Avenue in the Bronx.

The conversation, in which Peluso discussed Barney’s alleged role with unusual clarity and detail, began with the men discussing suspicions Coppola’s relatives and the feds had that Bellomo was involved in the slaying.

“Ralphie Coppola’s sister, she told the agents that this could never have happened without Barney giving the okay,” Peluso said.

“Well,” Ardito replied, “they got him down [for it]. That’s why he’s doing so much f—ing time [in prison].”

At that point, Peluso spelled it out for Ardito, confirming what Coppola’s relatives and the feds had suspected when he went missing on September 16, 1998.

“John,” Peluso said, “he was in the can. He was in the can. They came to me, ‘When are you going to see Barney? This is between us. Tell him we’re having a lot of trouble with Ralphie. How does he feel if we do what we got to do?’

“I went there. I took Barney by the machines where you buy the sandwiches. He said, ‘Pete, I’m in here. They’re out there.They know what’s what.They got to do what they got to do. They got to do it.’ I came out, and two days later he was gone.”

Peluso will surely expand on his remarks from the witness stand. Several months after the lawyer implicated himself and Bellomo in Coppola’s murder, he became a turncoat, and wore a wire for nearly a year. But none of the resulting conversations, nor anything he can say from the witness stand, is likely to have the impact of the words he uttered on July 31, 2004, when he didn’t know the feds were listening.

Not so, Bellomo’s lawyer Barry Levin, says. “The guy’s a big windbag,” Mr. Levin said, and asserted that during the lengthy probe, Peluso was heard contradicting himself numerous times. “He’s making up stories to try and make himself feel important, and to impress the people he’s talking to. At one point he says he doesn’t know who’s running the Genovese crime family, and asks, ‘Who’s in charge?'”

This column and other news of organized crime will appear later today at ganglandnews.com.