NEW YORK (CBSNewYork/AP) — A turncoat mobster is telling the inside story of a historic heist immortalized in the hit Mafia movie “Goodfellas.”

Gaspar Valenti testified Tuesday at the federal trial of an aging gangster charged in the $6 million Lufthansa robbery in 1978.

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Valenti told a Brooklyn jury he was a mob associate when defendant Vincent Asaro, his cousin, asked him to join a robbery crew for an armed holdup at a cargo terminal at Kennedy Airport.

He testified that it was believed there was $2 million at the terminal. He said when the bandits ended up with $6 million, there was elation. The joy turned to fear that they’d be robbed themselves once word got out about the score.

Valenti told jurors Asaro urged him to “make sure you do everything you’re supposed to do.” It wasn’t until the night of the robbery that Valenti learned Asaro would not take part, the witness testified. Valenti admitted that he did.

Valenti testified that he and Asaro each got a $750,000 cut.

Asaro listened to the testimony intently. He sometimes jotted notes on a yellow legal pad.

The 80-year-old blew kisses to family members during a break.

Asaro’s name hadn’t been associated with the robbery until his arrest last year.

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Prosecutors have described Asaro as a cold and callous killer, murdering a suspected informant by choking him with a dog chain and burying him in the cellar of a Queens home.

The defense has asked the jury to question the credibility of the former gangsters set to testify against Asaro — career criminals with 22 murders among them.

Asaro, who has a history of convictions for lesser mob-related crimes, was arrested again after Valenti came forward with new information about the heist and agreed to wear a wire to try to coax admissions out of the reputed longtime member of the Bonanno crime family.

Prosecutors haven’t revealed why their key witnesses turned on Asaro, though it’s believed he may have held a grudge after being cheated out of a cut of Asaro’s $750,000 take from the heist, said Jerry Capeci, a Mafia expert who writes for GanglandNews.com.

The theft was orchestrated by James “Jimmy the Gent” Burke — a late Lucchese crime family associate portrayed by Robert De Niro in “Goodfellas” — with the blessing of Asaro, whose crime family considered the airport its turf, court papers said.

Mobster Salvatore Vitale testified Monday that he saw Asaro give a case filled with jewerly from the Lufthansa heist to a Bonanno family capo and received a gold necklace in return.

Also expected to testify is former Bonanno boss Joseph Massino, the highest-ranking mobster to ever break the mob’s oath of omerta by becoming a government witness.

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