Last year, the Boston Herald identified George Reissfelder, a mob associate who'd died in 1991, as a potential suspect. Shortly thereafter, the inmate, Robert C. Beauchamp, contacted the FBI and said that in 1991 Reissfelder had told him that the stolen artworks — including three Rembrandts, a Vermeer, a Degas, and a Manet — were hidden in the Maine home of a recently deceased associate.
Reissfelder died soon after, without revealing the specific location of the Maine house.
"We have acted upon the information, but we have been unable to corroborate it," said a spokeswoman for the FBI's Boston office.
The museum, meanwhile, is skeptical. "The information provided by this individual in the past has not led to any significant development in the case," it said in a statement.
The FBI searched a house in Lewiston, Maine, last year on a tip from Beauchamp, without turning anything up.