The Concert by Dutch painter Johannes Vermeer is one of the artworks thought smuggled by James ‘Whitey’ Bulger

An ex-met detective has claimed that murdered mob boss James 'Whitey' Bulger gave stolen art worth half a billion dollars to the IRA.

Charles Hill, a former Scotland Yard detective turned private investigator, said he believes Bulger was involved in the unsolved theft of 13 works of art from the Isabella Stewart Gardner Museum in Boston in 1990.

The missing paintings include Rembrandt's Christ in the Storm on the Sea of Galilee, his only known seascape, and Vermeer's The Concert, and the heist is regarded as the biggest unsolved art theft in world history.

While the museum has offered a $10m reward for the safe return of the celebrated works, Hill has said he believes they are stashed away somewhere in the Republic.

The Irish-American crime boss has gone to the grave without ever revealing whether he had a hand in the theft of the art. Bulger (89) was found dead last week in federal prison in West Virginia, where he was serving two life sentences for 11 murders.

However, speaking to The Observer, Hill said Bulger was key to solving the crime.

"Even the dogs in the streets of South Boston must have known Whitey was involved in some way before, during or after the robbery," he said.

"Even if Bulger did not order the robbery originally, he would have muscled in and taken control of the haul soon after it took place.

"Whitey was an IRA sympathiser and was involved in arms deals and drugs shipments to the Republic.

"After a shipment of weapons and ammunition was intercepted by the Irish navy in 1984, Whitey felt he owed one to his friends in the Republic.

"I believe he offered them the paintings."

The paintings have not been seen in public since they were snatched from the museum in a raid carried out by two men dressed as police officers in the early hours of March 18, 1990.

After conning their way into the building on the pretence of investigating a disturbance, they handcuffed the security guards and spent 81 minutes in the galleries before escaping with the art.

Anthony Amore, the museum's security chief, has rejected Hill's theory, although he is not the only person to suggest the paintings might be in the possession of the IRA

In January, Arthur Brand, a Dutch investigator and art adviser based in Amsterdam, claimed the works were in Ireland.

"The FBI have been in Ireland many times because they've had strong leads for the art being in hands of the IRA, but some people think they're still in America," he told The Guardian.

"I have spoken to former IRA members who say it was common knowledge these paintings were probably in the hands of the organisation," he said.

"One said, 'I heard we had them'."

Belfast Telegraph