NEW YORK (CBSNewYork) — A cleaning crew with the Metropolitan Transportation Authority mistakenly tossed out photos of a 9/11 tribute.

As WCBS 880’s Peter Haskell reported, the artwork was placed in the World Trade Center subway station as an homage to September 11th.

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Artist Keith de Cesare had pictures of the memorial he had created in 2001.

“Photographs with children leaving flowers, photographs of details of what people had left behind,” he told WCBS 880.

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He says he posted the photos on 9/11 and came back on the 12th.

“And I saw through the train that the wall was clear, my heart sunk. ‘Oh my God, they’re gone’,” he recalled.

De Cesare says he was told that an MTA cleaning crew ripped the pictures down and threw them away.

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The transit agency says they’re looking into it.