Box of Goblins: The Case of the Spirits in the Boxes

Mouryou no Hako: Chuuzenji Atsuko no Jikenbo - Hako no Yurei no Koto

A side story that reveals the investigative notes that Atsuko, the younger sister of the main character Akihiko Chuzenji, wrote about the brutal dismembering incidents in the main story. (Source: ANN)