THE HAGUE, Aug. 20 (Xinhua) -- Sotheby's in London has auctioned an artwork by Dutch artist J. J. Schoonhoven, despite a warning it was stolen, Dutch newspaper NRC reported on Tuesday.
The work, a papier-mache relief, was one of several art pieces stolen from the Bommel van Dam museum in Venlo in March 2013. Together they had a value of over 1 million euros (1.3 million U.S. dollars).
According to the newspaper, Sotheby's ignored a warning from the Art Loss Register, a database of stolen artworks.
The work -- dating back to 1969 -- was sold under a different name and had been turned 90 degrees in the sales catalogue.
Dutch museum director Rick Vercauteren said it was incomprehensible that this could have happened.
"It baffles me that a work that is registered with the Dutch National Police Agency, Interpol and the Art Loss Register can be sold 12 weeks later," he was quoted as saying.
The sale came to light last week when an art expert who tracks stolen works brought two other stolen works of Schoonhoven to the police in Amsterdam.
Meanwhile, Sotheby's had also been to the police after the buyers became suspicious about the provenance of their new purchase.
The work was offered to Sotheby's by a dealer who also possessed the other stolen works. He was arrested last week in Amsterdam.
Sotheby's has declined to comment on the claims citing the ongoing police investigation.