SPOILERS: Holy Crap, what a good episode. It truly but the UNKNOWN in Unsub. It was an episode full of twists, that never let you know who was the victim and who was the villain until the end.
This was the first episode of Criminal Minds I've watched in a while, and I wasn't disappointed. 3 Unsubs. A Copycat, a Victim no more and The Piano Man. I can't get over this episode, it's my favorite so far.