It has been 23 years since the public has seen originals of the artwork by Rembrandt, Vermeer and Degas among others at Boston's Gardner Museum.
They are, in fact, part of the most valuable property theft in the United States.
The museum continues to offer its original reward of $5m for recovery of the artworks in good condition.
The Federal Bureau of Investigation (FBI) now says it believes it knows who was behind the art heists - but wants help in apprehending the suspects.
Al Jazeera's Tom Ackerman reports.