"This is a murder mystery novel," Christopher announces (7.1).
Siobhan had told him to write something he would like to read himself, and he likes murder mystery novels (particularly the Sherlock Holmes ones). So there you have it.
Siobhan says that murder mysteries are usually about the murder of a person, and it would be pretty unusual to write one about a dog.
But Christopher quickly offers up a few reasons why writing about the dog is okay: (1) he likes dogs; (2) he wants to write about something that really happened to him, because he has a hard time imagining things; and (3) he doesn't know any people who have been murdered. Pretty sound reasoning, right?
He also mentions that some dogs are "more clever and more interesting" than some people – particularly the ones in his class (7.8). Ouch!