Kindaichi Shonen no Jikenbo S01E05 - ファイル５: 首吊り学園殺人事件

Teacher of a special class asks Kindaichi to join the class in order to uncover who is killing chicken and writing a lullaby words in blood. And after each killing, the hair on the woman in the painting grows longer. It doesn't take long for students to start dying, which is attributed to curse since all of them bullied a student who committed suicide. All leads point to their teacher, but Kindaichi tries to disprove that only to find himself mislead by his own reasoning.