Ridiculous movie
Movies like this that are rated so highly by critics and IMDB users is why I no longer have faith in reviews/ratings.
Soo-Hyeon decides to catch the killer and then keep releasing him as some sort of game, he doesn't give a crap about the damage he does whilst he released back into the public.
From my memory a school girl is almost raped, a nurse is forced to perform oral sex, a taxi driver and passenger are killed, the pharmacist probably died, and his fiancée's father and sister are also dead or thereabouts.
He then tops it off by making the killers family, who have disowned him, visit their son/father and see his head chopped off. Brilliant stuff.