According to a Q&A column in The New York Times, at least two major New York museums still have Banksy artworks that were surreptitiously placed there by the mysterious street artist nearly a decade ago. The Brooklyn Museum is storing a painting of a Colonial-era officer with a red coat holding a can of spray paint with anti-war graffiti in the background. Sally Williams, a spokeswoman for the museum, told the Times: “We have it in our custody, but as it was never offered to us for inclusion in our collection, we have not accessioned it.” Asked why the museum had not returned the painting, Williams said, “we don’t know how to return it to its rightful owner.”

Meanwhile at the Museum of Modern Art, Banksy left a painting of a can of cream-of-tomato soup in an elevator. That work was taken down in accordance with security policy and was available to be picked up by the artist, according to museum spokeswoman Margaret Doyle. “I don’t believe he ever retrieved it,” she said.

According to the column, the Times had not received responses for inquiries made to the Metropolitan Museum of Art and the Museum of Natural History about works Banksy left at the respective institutions. Some of Banksy’s works have achieved high prices at auction. The record is for Keep It Spotless (2007), (a playful jab at Damien Hirst), made of household gloss and spray paint on canvas, that sold for $1.9 million at Sotheby’s New York in 2008, soaring above expectations of $250–$350,000. According to the artnet database, roughly 1,165 Banksy works have appeared at auction to date.

The database describes the unknown artist as “British-born, circa 1974.” As the Times points out, “Banksy’s identity is as obscure now as it was then… It is generally thought that Banksy is a single person, not an underground collective, although there are imitators.” Which of course raises the question, how do we know if any of these works are actually his?