The alma mater of Kuroko's Basketball manga creator Tadatoshi Fujimaki and other locations linked to the author were sent threat letters with an unknown powder and other substances earlier this month. According to the police, the Toyama High School in Tokyo's Shibuya ward received a threat letter with the powder on Tuesday. Sophia University received a hydrogen sulfide-like liquid and a letter last Friday.

In addition, a publisher in Tokyo's Suginami ward received powdered barium and a threat letter on Saturday. The letter warned about Kuroko's Basketball , saying, "If you do not stop the parody manga, you will get hydrogen sulfide" and other similar threats.

FNN posted a video report on the incidents.

Source: FNN via Uri-Sure Matome+

Update: Headline's ambiguous wording changed. Thanks, Dessa.