If its the same as the book, then you are wrong. But I don't wanna spoil it for you unless you really want to know because other people have asked for spoilers and then had a go at me when I have told them. You are close about Sam though.

I was totally thinking that too, richieban! Ever since the ep. where he is seen running through the woods. I was sure that he was a werewolf, but after last night's ep, I'm thinking that's not the case :)

he technically could change into a wolf but he prefers dogs

Sam is a shapeshifter.. not a werewolf.. but would be nice if he change for something more interesting. Dog is kinda boring.