Christopher sets out to do some more detective work. He decides to ask his neighbors if they might know something about who killed Wellington.
Usually he doesn't like talking to strangers – not because it's dangerous, but because he just doesn't like people he doesn't know.
But, just in case, he always carries his Swiss Army knife in his pocket.
He makes a map of his street, and starts knocking on doors, but no one knows anything at the first few houses he checks.
Then he goes to the house of a woman called Mrs. Alexander who's super friendly: she says she recognizes Christopher from seeing him go to school every day.
Christopher is a little confused because she's "doing what is called chatting where people say things to each other which aren't questions and answers and aren't connected" (67.67). We hear you, Chris.
She invites him inside for tea, but he says he doesn't go into other people's houses. Oh, and he only drinks orange squash. Mrs. Alexander says she'll bring some outside then, but while she's inside, Christopher starts getting worried that maybe she's calling the police. So he leaves.
On his way back home, he comes up with a way to figure out who might have killed Wellington. He just needs to figure out who would want to make Mrs. Shears upset.
Hmmm. Christopher only knows one person who doesn't like Mrs. Shears, and that's – wait for it – Mr. Shears. Aha.
Mr. Shears left his wife two years ago and never came back. (That's partly why Mrs. Shears cooked for him and his father after Christopher's mother died: she was lonely and needed company.)
(He also mentions that sometimes Mrs. Shears slept over at their house, and kept things tidy in the kitchen.)
Christopher doesn't know much about why couples get divorced, but he figures it's because they hate each other. And if Mr. Shears really hates Mrs. Shears, he might have come back to the house to kill her dog. You know, to make her cry.