Board Thread:False Info and Speculative Discussion/@comment-31079951-20170130191122/@comment-26819589-20170131013646

^^^ Because of the spiral that was found on the deer. As you know. The werewolves sign for a vendetta is a spiral. So Laura came looking(I don't think Laura knew if the werewolf she was looking for was an alpha or not) to see why this mysterious werewolf was out for revenge. I think Derek just assumed that his sister had been looking for an alpha werewolf the whole time. After Scott revealed that the alpha made a spiral on the car(his way of putting two & two together).

^ Peter admitted he killed her. But said it was unintentional(which was a lie). It was Scott who revealed(while rescuing Derek)that Peter had lured Laura back to beacon hills with the purpose of taking her status. 😎