It was just another sunny summer day in Haarlem, Netherlands, when an unusual request landed in Dutch antiquarian bookseller Pieter de Vries’ inbox.

A woman named Natalia, identifying herself as being with a company called “2077AI,” was looking to source what she described as a “fairly large order” of books. Attached was a spreadsheet listing more than 3,000 ISBNs along with instructions to match titles, prepare quotes and estimate shipping costs directed to China.

De Vries barely looked at it, dismissing the message as spam or phishing without reading past the first few lines. It wasn’t until weeks later, when a Dutch journalist investigating the procurement request contacted him, that he learned of the request’s connection to artificial intelligence.

“I was shocked!” said de Vries, who provided Fortune with the email and subsequent spreadsheet containing 3,001 titles, mostly published between 2020 and 2021 by academic publishers like Emerald Publishing, Elsevier, Wiley, Routledge and Oxford University Press, and ranging from business and education to engineering, public policy and medicine. “Very unusual,” de Vries said. “That’s why I regarded the request as spam or phishing.”

De Vries wasn’t the only one. He told Fortune several other Dutch antiquarian booksellers received the same request and, like him, dismissed it. (They didn’t take “it seriously” and “considered it as scam,” he said). While the inquiry had little effect on his business, he said, it could have been a different story for booksellers who specialize in selling secondhand books at scale.