SOS - Save Our School(2012)

Original title: SOS - 우리 학교를 구해줘

A fire starts in a classroom and two students are trapped in that burning classroom. One of the students died and one was taken to the hospital unconscious. People suggest it was suicide and some say it was murder. Detective Kim Eun Sup is staking out while the student is dying before he gets called in on the site. He then witnesses the most terrible thing there.