Herne Bay, a town about 60 miles east of London, has fallen prey to a new kind of ripper. According to The Guardian, a criminal known as the “Book Ripper” has torn pages within about 100 books in a charity bookstore before placing them back on shelves.

“I’m trying not to be too Sherlock Holmes about it,” Ryan Campbell, chief executive of the charity Demelza, told The Guardian, “but if there’s such a thing as a quite distinctive rip, well, he or she rips the page in half horizontally and sometimes removes half the page.”

Though it’s not the most efficient way to ruin a reading experience, since the pages themselves are still legible as long as they’re left in the book, it’s still devastating to a shop that relies on the generosity of others to serve the underprivileged.

“Of course people donate these books towards the care of children with terminal illness so it’s almost like taking the collection box,” Campbell said.

Since the occasional torn page in a secondhand bookshop isn’t uncommon, booksellers didn’t immediately realize the scope of the issue, but they believe it's been happening for a few months. The Book Ripper targets bookshelves that can’t be seen from the register, and has a favorite genre to vandalize: true crime.

The local library has also reported the same pattern of damage in some of their volumes, and police are now monitoring the situation in both places.

Townspeople are monitoring the situation, too, patrolling bookstores and libraries hoping to apprehend the culprit.

“I’m a little worried about the person,” Campbell said. “It makes you think a little bit about who’s doing this and why they feel the need to do it and what’s going on in their lives.”

[h/t The Guardian]