Into the Mirror (2003)

Now this Korean film is one very creepy, scary story, unless the idea of your mirror image having a murderous life of its own doesn't frighten you.  The story concerns an ex-cop who has left the force after bringing about his partner's death by shooting the villain's mirror image, who is now head of security at a fashion department store, run by his uncle, which is about to re-open after a fatal fire.  In the days prior, a number of strange deaths occur, all related to mirrors, of employees from before the fire.  Another rival cop begins to investigate, convinced that a serial killer is afoot, but rumour has it that a ghost is the more likely culprit.  While not 100% logical (are horror films ever completely logical), the Korean belief that the mirror image you see may well be another person, expecially if one is killed within a mirror, leads to a truly eerie conclusion.  The movie is stylishly framed which helps a lot towards overlooking the occasional bits that don't really make a lot of sense (unless of course you are Korean).