Brooklyn prosecutors are seeking to line up a star witness for their sensational upcoming trial of a former FBI supervisor, R. Lindley DeVecchio, who is charged with helping legendary mob capo Gregory Scarpa commit four murders.

The prospective witness is none other than Gregory Scarpa Jr., the imprisoned son of the late Colombo crime big, who after his death in 1994 was revealed to have been a much-prized government informant (and whose handler was Mr. DeVecchio). Unfortunately, the would-be witness comes with heavy baggage: He’s already been called a perjurer by a federal judge and other authorities.

So far, the matter is still in the talking stages. Gang Land has learned that Scarpa has told prosecutors he wants to testify at the trial. The Brooklyn district attorney’s office, which filed the blockbuster charges against Mr. DeVecchio, has been talking to him with a view toward granting his wish.

If so, he would undoubtedly have a lot to say.

Scarpa could give a detailed, shot-by-shot account of the slaying of Mary Bari, a onetime paramour of a top Colombo gangster who was killed in 1984, as well as the 1987 murder of mobster Joseph “Joe Brewster” DeDomenico. According to court records, Scarpa fired the fatal shots at DeDomenico and held down Bari as his father shot her at a mob social club. Mr. DeVecchio is alleged to have alerted Scarpa Sr. that both were potential informants.

Soon after the Joe Brewster slaying, Scarpa became a fugitive, allegedly after Mr. DeVecchio tipped his father that he was going to be arrested on drug charges. Captured later, Scarpa was convicted in 1988 and was in prison when two other murders that Mr. DeVecchio is alleged to have aided — that of Patrick Porco in 1990 and Larry Lampesi in 1992 — took place. If he professes any insight about those killings, it would have to have been acquired secondhand.

Prosecutors have been secretly discussing those events with Scarpa Jr. since December 6 in a secure wing of the Metropolitan Correctional Center.

On that day, according to Bureau of Prison officials, Scarpa Jr., who is serving 40 years for racketeering charges and is slated for release in 2035, was moved to the MCC. Since 1999, he had been at a super-strict Colorado facility that, at latest count, is home to the 465 “most violent” inmates of the 193,643 incarcerated around the country.

The Executive Assistant Warden, Scott Sussman, confirmed that Scarpa, 55, is at the MCC, which primarily houses transient inmates with court proceedings or other official sessions scheduled in the New York area, but declined to provide any reasons for his transfer.

A spokesman for the district attorney’s office declined to comment about the matter.

Sources who are familiar with the situation but not involved in the case have told Gang Land that Scarpa and the Brooklyn district attorney’s office began weighing the possibility of him serving as a prosecution witness even before he was relocated to the MCC in December.

It would obviously be a risky move, as the imprisoned mobster, who testified at his own trial and at a hearing for convicted acting Colombo boss Victor “Little Vic” Orena, has been publicly called a liar by federal authorities.

If he were to take the stand against DeVecchio, there is little, if anything, that the state prosecutors could do for Scarpa, who received nothing from the feds for information he provided about terrorists Ramzi Yousef and Terry Nichols.

Sources say that the jailed gangster is willing to testify without any guarantees, and that the DA’s office is seriously considering the option.

“He’s got nothing to lose,” a law enforcement official said. “He’s 55 and he’ll be in his 80s before he can get out. Things can’t get worse; only better. And until his work is done, he’s close to home, and can get visits from loved ones, if he has any.”

Scarpa wouldn’t be the first incarcerated gangster to cooperate with the feds on a wing and a prayer.

Leroy “Nicky” Barnes, the legendary Harlem heroin merchant who was serving life without parole in 1981, got out 17 years later after he turned and helped convict 44 drug dealers and murderers, including a few mob associates, of various crimes. Barnes, by the way, has co-authored a book about his life, “Mr. Untouchable,” due out next month.

Speaking of books, Scarpa is writing one with Sandra Harmon, who has given an affidavit to the DA’s office containing allegations of wrongdoing by Mr. DeVecchio that she claims to have obtained from the elder Scarpa’s former partner, Linda Schiro, while the two women were collaborating on a book project that failed to materialize.

Ms. Harmon told Gang Land she had loyalties to Scarpa and the DA’s office and refused to discuss where Scarpa is or whether he and Brooklyn prosecutors have spoken to each other.

“But I know why someone would want to leave Ad Max” she said, using the BOP’s shorthand term for the Administrative Maximum facility in Florence, Colo. “It’s a hell hole, all about shackles and a 23-hour-a-day lockdown. And he does have children, a brother, and other relatives he loves.”

News of Scarpa’s willingness to be a prosecution witness came as the judge in the case rejected a prosecution motion to postpone the trial until after Labor Day to enable lead prosecutor Michael Vecchione to try two corruption cases, those of Judge Gerald Garson and Clarence Norman, for the fourth time.

This week, a Supreme Court justice, Gustin Reichbach, told assistant district attorneys Noel Downey and Bryan Wallace that the quadruple homicide case — in which a co-defendant has been held without bail for 11 months — was more pressing. Assuming he rejects voluminous defense motions to dismiss the case, the trial would begin in mid-May, the judge said.

In court papers, defense lawyers Douglas Grover and Mark Bederow charged that the grand jury investigation was tainted by numerous prosecution leaks to Gang Land and others, and by prosecutors’ use of evidence that Mr. DeVecchio provided on two occasions when he had been granted immunity.

Reached by Gang Land, Mr. Bederow said he was reluctant to “speculate” about witnesses prosecutors think may be “helpful to their case. But certainly, if they intend on using Gregory Scarpa Jr., we would welcome the opportunity to cross examine him.”

***

Three decades ago, mob associate Ernest Malizia knew exactly what to do after an undercover operative named Boom Boom busted him in a drug sting and he was sentenced to heavy time and stuck in the old federal detention center on West Street.

On September 22, 1974, with the help of a priest and a $50,000 bribe to a corrupt prison guard, he walked out the front gate and flew to Miami. He lived large for three years until his pursuers collared him and he was sent off to more secure accommodations.

Today, at 74, Malizia suffers a host of debilitating medical problems, is broke, and his last resort against dying in prison the same way his brother did three years ago lies with a Manhattan federal judge, Deborah Batts, his devoted wife, Brenda, says.

“He’s had quadruple bypass surgery, needs a defibrillator, has no spleen to help him fight infection and has been rushed to hospitals several times in recent months with infections and heart complications,” Malizia’s wife, who has joined her husband in filing letters seeking mercy from Judge Batts, says.

After getting paroled from prison in 1994, Ernie was clean for a while. But truth be told, he got popped again for drug dealing, pleaded guilty, was sentenced to eight years, which he completed last year.

Before he could be released, however, he was hit with parole violations stemming from the same charges for which he had been sentenced, and ordered to serve an additional 12 years. This seems a bit unfair to Brenda Malizia, and Gang Land, too.

This column and other news of organized crime will be available today at ganglandnews.com.