This discussion may contain spoilers!
I think the murderer is Bigby, maybe it is not him, but the wolf inside him. I have some evidence.
1. The victims heads were cut off (by a claw?)
2. The heads were found after Bigby was unconscious (a possible window for the wolf to take over?)
3. Bigby knows the scent of snows perfume (maybe confused the wolf into attacking Lilly?)
4. In room 207,it is revealed the murderer smokes huff 'n puff cigarettes (the same kind Bigby smokes)
5. In a video the mirror says "friend will turn on friend, at the end of the end.
1 day later
you guys are probably right, my theories are rubbish, but I started this post not only to put out my theories, but also so you can put out yours, so can ihave some of your theories, please?