Sensei, Kowai Hanashi Shimasenka?

Sensei, Kowai Hanashi Shimasenka?:

TRIGGER WARNINGS: RapeStrange rumors, mysterious legends, and suspicious corpses...Hizuki Reiji is, by all accounts, a normal high school Japanese teacher, but he's thrust into the middle of a mystery when he moves to another town for a substitute teaching position. The woman he's replacing disappeared two weeks ago, and rumor has it that the problem child of her class, Magaki Kyoichi, was seen with a blood-stained knife the day before she vanished. The cops are on his trail, but what really happened to Sakuraba-sensei? And how are Hizuki and Magaki involved?