I was reading on another site that the killer was Sean. Apparently he returned on Christmas Day to see Amy, overheard Bradley and Archie arguing about Stacey's rape and became incensed. He waits till Bradley leaves and then kills Archie.
How probable does everyone think this is? I'm sure Sean swore never to return unless it had to do with Roxy's exit??
Also I think I would feel very let down after them building up half the cast for the Whodunnit only to find out they had brought in an outsider.
What are the thoughts on the above - outsider or cast member?