The FBI says it knows who made off with $500 million in art from a Boston museum in 1990 — but it can't find the works themselves. There's a $5 million reward for the location of the 13 pieces listed here.

The Federal Bureau of Investigation announced today that it knows the identity of the thieves who stole 13 works of art from the Isabella Stewart Gardner Museum in Boston more than two decades ago, in what’s widely viewed as the biggest art heist in U.S. history. But the agency is still trying to figure out where those pieces are.

“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 for the theft,” Richard DesLauriers, special agent in charge of the agency’s Boston office, said in a press release. “With that same confidence, we have identified the thieves, who are members of a criminal organization with a base in the Mid-Atlantic states and New England.”

On Mar. 18, 1990, two men dressed as police officers gained entry to the museum, tied up the security officers and swiped 13 works worth an estimated $500 million, according to The Associated Press. They include several sketches by Edgar Degas, The Storm on the Sea of Galilee, the only seascape ever painted by Rembrandt Van Rijn, and The Concert, one of only 36 paintings by Johannes Vermeer that still exists. Here’s a gallery of the missing work, below; if any of these look familiar, you might want to go ahead and contact the FBI: the agency is offering a $5 million reward to anyone who reports their location.

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Édouard Manet, Chez Tortoni:

FBI

Govaert Flinck, Landscape with Obelisk:

FBI

Johannes Vermeer, The Concert:

FBI

Rembrandt van Rijn, A Lady and Gentleman in Black:

FBI

Rembrandt van Rijn, The Storm on the Sea of Galilee:

FBI

Rembrandt van Rijn, Self-Portrait:

FBI

Edgar Degas, La Sortie de Pesage:

FBI

Edgar Degas, Cortege aux Environs de Florence:

FBI

Edgar Degas, Program for an artistic soiree (1):

FBI

Edgar Degas, Program for an artistic soiree (2)

FBI

Edgar Degas, Three Mounted Jockeys:

FBI

Bronze Eagle Finial from a Napoleonic battle flag

FBI

A Chinese Ku, or beaker, from the Shang Dynasty (1200-1100 B.C.)

Isabella Stewart Gardner Museum

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