"We first noticed damage to the book at the end of January last year and it has been going on since then," Saeko Nishimura, a spokeswoman for the Japan Library Association, told The Telegraph.
"We do not know who is doing it or why they are doing it," she added, "But the police are now carrying out an investigation."
Pages have been torn out of the books, according to police, who are examining closed-circuit footage from libraries that were targeted. In many cases, the pages contained the same passages of text, leading police to suspect that the same person is causing the damage.Nishimura said that undamaged copies of the book have been removed from the shelves of many libraries in Tokyo. The Diary of a Young Girl is on the syllabus in many Japanese schools.
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