Public Enemy Returns (2008)

After aimlessly hopping crime scenes for five years, detective Kang Cheol Jung hands in his resignation in the face of major financial burdens. His chief, however, asks him to stay on until a high school murder case is closed. At first, it looks hopeless, but then Kang finds a fingerprint lead, and later learns that three of the dead student's friends are employed by a single company. He begins to investigate the group and its leader, Lee Won Sul. (Source: Asianmediawiki)