Diary Of June (2005)

The film tells the story of Detectives Chu Ja Young and Kim Dong Wook, who must solve a puzzling murder case involving a string of deaths at a local high school. Their investigation eventually leads them directly to a middle school student who has long suffered abuse at the hands of school bullies. In fact, each murder occurs just as it is described in the student's diary. On that evidence alone, one might think the detectives have an open and shut case. However, there's one problem. The student is already dead!