A sculpture cherished by the Art Institute of Chicago as an original work from 19th century French artist Paul Gauguin has been exposed as a forgery by Scotland Yard.

The stoneware sculpture titled “The Faun,” representing the mythological half-man half-goat creature, has been on display at the Art Institute of Chicago for a decade and now the museum has announced that the artwork is actually fake.

The museum recently learned that the sculpture is one of several art forgeries created by the Greenhalgh family of Bolton, England, a family of expert forgers, reports the New York Times.

The sculpted fake was reportedly produced in the 1990s (more than a century after the original sculpture had been created by Gauguin) and acquired by the Art Institute in 1997 from a London dealer, Libby Howie, who had acquired it at a Sotheby’s auction in 1994 for £20,700.

The amount spent on the supposed Gauguin artwork has not been revealed. The Art Institute is now seeking compensation from Sotheby’s and the private dealer.

The Greenhalghs appear to have been successful as imitators of original art, according to reports. They have managed to sell their forgeries before. An imitation of the Amarna Princess, considered to be more than 3,000 years old, was bought by the Bolton Museum for £440,000 in 2003, after being authenticated by the British Museum, according to the Times.

The family apparently struck Scotland Yard as dubious some two years ago, after an attempt to sell the British Museum an Assyrian relief. They were eventually exposed as operating thus: Shaun Greenhalgh, 47, forged the artwork, while his parents, George, 84, and Olive, 83, handled the sales.

Son and mother were recently sentenced on charges related to this forgery, reports the Times, to 4 years and 8 months in prison and a suspended term of a year, respectively. The father is awaiting sentencing.