Scott's chem teacher. In the last episode, at the end it showed the Alpha morphing back into a human and it looked a lot like him. But who knows.
I just know that it's not Stiles, Lydia, Jackson, or Allison. Allison said that she was suspicious about her dad when she was talking to Kate. And Jackson either seems suspicious because he REALLY likes Allison and wants to make Scott mad or he knows something about the Alpha. But obviously he knows that Scott's a warewolf now because in the previews for the next episode , he's messing with Scotts head by wispering to him from across the cafeteria and knows he can hear him.
