Jigyaku no Uta Another Birthday

Seven years ago a large number of patients, nurses, doctors and other staff members got killed in a national hospital. The detective who investigated the case found death from a spear. Main character is detective's relative who wants to abandon school to continue investigation. At his class there is a girl who continues to cut her wrists because of the hell she lives in. What will be the consequences of their suffering and battle?

[From vndbreview]