An 82-year-old gangster’s imminent release from prison is reigniting interest in the world’s biggest unsolved art heist.

Federal officials believe Robert “The Cook” Gentile has information about the $500 million heist in 1990 from the Isabella Stewart Gardner Museum in Boston, but the almost-free wiseguy insists he knows nothing. He has been described as the last surviving person of interest in the case.

Gentile is scheduled to be sprung March 17 at the conclusion of a federal prison sentence for an unrelated weapons possession charge, according to the Associated Press.

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On March 18, 1990, thieves posing as cops cuffed two security guards and made off with 13 valuable works of art by Rembrandt, Vermeer, Manet and Degas worth more than half a billion dollars.

The paintings, which included Rembrandt’s only known seascape – Christ in the Storm on the Sea of Galilee – and Vermeer’s The Concert have never been found.

In 2013, the feds searched Gentile’s home in Connecticut and found a handwritten list of the stolen works and their estimated worth on the black market.

Prosecutors said a polygraph showed Gentile was almost certainly lying when he denied knowing where the paintings were.

Two years ago an independent art investigator told Fox News he was convinced the stolen artwork was in the possession of associates with the Irish Republican Army somewhere in Ireland.

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"I have been talking with several former IRA members — individuals I've built a trust with over the years," investigator Arthur Brand said. "I'm convinced they are there. The Ireland angle has been one of the most promising leads from the beginning."

The museum's website tells the story of the heist.

“Today empty frames remain hanging in the museum as a placeholder for the missing works and as symbols of hope awaiting their return,” says one panel.

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There is also a $10 million reward for information leading directly to the recovery of the art.