Anne Frank’s “The Diary of a Young Girl” and several books about the young Holocaust victim have been vandalized in the public libraries of Tokyo since earlier this year.

Dozens of ripped pages in these books have been found. There have been at least 265 damaged books accounted for at 31 different libraries since the end of January.

Police have started an investigation because the motive for damaging these books remains unclear.

Chief Cabinet Secretary Yoshihide Suga called the vandalism “shameful,” adding that Japan would not tolerate this behavior.

According to city official Mitsujiro Ikeda, the books were damaged in the reading rooms of the Nakano district libraries.

“Books related to Ms. Anne Frank are clearly targeted, and it’s happening across Tokyo,” he said. “It’s outrageous.”

Though one library has moved several books (relating to Anne Frank) behind the library counter for protection, they can still be rented.

Anne Frank’s diary has is about the young girl’s experience hiding during the Holocaust. Frank was later caught, and died in a concentration camp when she only 16 years old.

A U.S. based Jewish human rights organization called the Simon Wiesenthal Center, believes that this vandalism is a hate campaign. They are  currently urging authorities to find those responsible.