Amazon is facing fresh scrutiny over the use of physical books for artificial intelligence training after an investigation reportedly tracked a shipment of hard-to-find titles to a company facility in Las Vegas, where workers allegedly cut the bindings from books before scanning their pages and eventually destroying them.

The investigation, reported by 404 Media, involved placing a tracking device inside a book from a large order and following its journey across the United States. The shipment ultimately reached an Amazon facility associated with an operation known as VGT3.

The discovery has raised concerns among booksellers, librarians and readers about what happens to physical books once they are acquired as potential sources of AI training data.