This discussion may contain spoilers!
EDIT: This is NOT the Crooked Man. On this original post. Scroll down to my reply to @woodywoodsman because that is our new suspect
Before you read this post, I highly suggest that you read this amazing post by @HeartLocker which has many strong supports as to who the killer is. Read it at your own risk because if it's right there are huge spoilers to the killer case. Link to the page right here
When Beauty mentions "The Crooked Man", I think she may be referring to the Red Head Guy
Yeah this guy. Well to my information, he is The Boy Who Cried Wolf. (Look at all the titles of the episodes and achievements for it to make a bit more sense). And also his tie in the picture has CROOKS. Do you know who uses a crook? A Shepard. Do you know who the Boy Who Cried Wolf was? A SHEPARD. Well my point is, connect "The Crooked Man" and the Boy Who Cried Wolf together and it actually makes sense. This just adds on to the fact that he IS in fact the Killer. But the question I'm asking now is why were Tweedle Dee and Tweedle Dum snooping around the crime scene if they knew their boss was the killer?
Again this is just a theory. Right? Wrong? You tell me.
Edit: I think I may have disproved this theory and with the help of @woodywoodsman . Go check out my reply because I think we may have found our Crooked Man