What do dogs mean to Christopher? Why do you think the identity of Wellington´s killer had such an impact on him? How does he try and deal with this information?

For Christopher, dogs, unlike people, are an open book. He understands dogs because they're straighforward. There aren't a million different actions, facial expressions, or words, like there are with people. Dogs are either happy, cross, sad, or focused. Wellington's killer impacted Christopher because it was his own father, something that will also tie in with his mother.... who his father successfully killed off until Christopher discovered differently.