HARTFORD, Conn. — The aging Connecticut mobster authorities believe has info on the infamous Isabella Stewart Gardner Museum art heist had a list of the paintings — with dollar amounts — in his home, and botched a lie detector test in which he claimed not to know the location of the 13 missing masterworks, prosecutors revealed Thursday.

The details emerged at the sentencing of Robert Gentile, a reputed 76-year-old made member of the Italian mafia who pleaded guilty in November to federal drug and gun charges.

Assistant U.S. Attorney John Durham said in court that during a February 2012 search of Gentile’s Manchester, Conn., home, authorities found a Boston Herald article dated a day after the 1990 heist that included a list of the 13 masterworks and corresponding dollar amounts of their estimated market value.

Authorities have said they’re worth more than $500 million, but are literally priceless because they would be impossible to sell without detection.

Durham, in arguing the heist was relevant to Gentile’s sentencing, also said that during an FBI-administered polygraph test, it was determined that there was a “99 percent likelihood” Gentile was lying when he said he didn’t know where the paintings were located.

Gentile’s lawyer, however, quickly discounted both claims, saying the list was given to Gentile by an associate of another man and that he kept it because he is a “hoarder.”

He also disputed the test results, which he said came under extreme conditions, including a threat by an investigator that Gentile would die in a federal prison if he didn’t cooperate.

“It wasn’t a polygraph, it was an interrogation,” attorney A. Ryan McGuigan said, adding that a defense expert refuted the reliability of the results.

The attorneys also sparred over the prosecutors’ claim that Gentile is a made mafia member and over wiretapped calls in which he mentioned other mobsters.

Among them, Durham said, was James “Whitey” Bulger, the notorious Southie organized crime lord who was on the lam for 16 years before his capture in 2011 and is set to go to trial next month on 19 counts of murder and racketeering charges.

“Mr. Gentile also made reference to Whitey Bulger” in one taped conversation, Durham told the court, drawing a quick rebuttal from McGuigan who said a mere mention of the mobster doesn’t mean he was involved with him.

“He’s telling me, ‘I never met Whitey Bulger,’ ” McGuigan said, adding later of the various mafia names dropped throughout the case, “He doesn’t want to pay for the sins of other people.”

Judge Robert Chatigny said the reference to the Gardner paintings and Gentile’s ties to organized crime members would all be taken into account as part of Gentile’s background and history, which included seven convictions, the most recent of which was in the mid 1990s.

But Chatigny said he also weighed Gentile’s age, health and his ailing wife before ordering him to 2 1/2 years in prison — below the 46- to 57-month recommended guidelines — with the possibility of release in 10 to 11 months. The judge also recommended Gentile serve his term at the Fort Devens Federal Medical Center, at Gentile’s request.

Gentile’s wife, wiping tears from her eyes after her husband was sentenced, left the courtroom with her son without commenting.

The lighter sentence came after Gentile addressed the court without mentioning the Gardner robbery, saying he “worked hard all [his] life” to support his family through a variety of construction jobs and often couldn’t say no to those who needed help.

“My heart is too big. That’s why I get in trouble sometimes,” he said. Gentile, fighting through tears, added that his wife is “very sick” and that he needs to be there to take care of her.

“You’re the only one who can help,” he told the judge.

The pleas came in stark contrast to the man Durham said stockpiled guns, silencers and what he called homemade explosives in addition to $22,000 in cash. Durham said Gentile also told informants that he was part of a million-dollar drug operation — all into his 70s.

Gentile was arrested on charges of illegally selling prescription pain pills, which he claimed was a set-up to press him on the missing paintings. Chatigny said there was no indication the defendant was “entrapped” and said the items found in his home indicate he is still involved “in a world that is on the wrong side of the law.”

Through his lawyer, Gentile has continually denied knowing anything about the world’s most intriguing and unsolved art robbery.

Authorities in March made the bombshell announcement that they know who committed the March 18, 1990, heist, and that the art had been taken through Connecticut to Philadelphia, where its trail went cold 10 years ago.

McGuigan said today that the only thing Gentile has admitted to in connection with the missing art is simply knowing Robert Guarante, a mobster who died in 2004 and whose Maine home was also searched by authorities as part of the investigation into the Gardner heist.

Distributed by MCT Information Services