FBI agents have descended upon the Connecticut house of an 80-year-old man who is believed to have been involved with the theft of artworks worth $500 million.

In 1990 two men walked into the Isabella Stewart Gardner Museum in Boston disguised as police officers. They overpowered the security guards, and left with 13 masterpieces including work by Vermeer and Rembrandt. Describing it as “the largest property crime in US history”, the FBI are offering $5m reward for the return of the paintings.

This the third time investigators have searched the home of Robert Gentile, a.k.a Bobby the Cook, who is currently in prison awaiting trial for firearm offenses. A handwritten list of the stolen works was found in his home four years ago, and last year he was recorded telling an undercover FBI agent that he had access to two of the stolen paintings.

Speaking in 2013, FBI Special Agent Richard DesLauriers said that they knew where the stolen art was and who the thieves were. “The FBI believes with a high degree of confidence that in the years after the theft, the art was transported to Connecticut and the Philadelphia region, and some of the art was taken to Philadelphia, where it was offered for sale by those responsible.”

However, Gentile’s lawyer Rome McGuian told ABC News that his client continues to deny the allegations. “He said, this is a quote, ‘They ain’t gonna find nuttin.'”

Any discoveries from this latest search have yet to be announced.