The unsolved mystery of the 1990 theft of a half-billion dollars of great art from Boston's Isabella Stewart Gardner Museum is legendary. It has a dedicated page on the FBI's website. A documentary, a book, and countless articles have chased the dragon of finding an answer to this question: who had stones big enough to pull this one off?
The FBI has revealed they might know the answer. Thing is, they won't name the suspects, and the suspects are dead.
So basically the guys who faked their way into the Gardner on that cold New England night (because there's no way a March night in Boston was warm) 25 years ago, wearing fake Boston Police uniforms, who made quick work of de-framing 13 masterpieces before vanishing back into the cold again—looks like they took their big secret to the grave.
However, as the Atlantic article pointed out, the Gardner Heist probably wasn't Hollywood slick:
The Gardner Museum heist occupies a unique place in American history thanks to its scale and its status as an unsolved mystery, but in many ways it’s fairly representative of art theft over the past half-century. Investigators don't think the thieves were art experts or sophisticates in the manner of a Thomas Crown or a Danny Ocean—or even master thieves like the Pink Panther gang. The stolen works were presumably difficult to offload thanks to their notoriety.
All that trouble and it may be that Vermeer's "The Concert" is sitting in someone's dusty Dorchester garage.
Even if a few old school cons shuffled off their mortal coils with their secrets secure, the feds haven't given up on pulling all the threads of the mystery apart in an effort to recover the masterworks. On August 6 the Dept. of Justice published security footage from March 17, 1990—the night before the crime—that added a new layer of mystery.
The ultra low-res surveillance cameras captured an interesting scene. A car resembling the thieves' vehicle parked in the spot they used. An unknown man exited, and ignoring Museum security rules, a guard allowed him to enter the Museum. This occurred almost exactly 24 hours before the heist.
Even if anyone who might get arrested for the Gardner Heist is gone, the mystery will persist—until the remaining $5 million reward for information leading to the artworks proves more powerful than keeping secrets.