The duality in Jumbo's nature has to do with the question the novel raises of who really killed Jorge. If you believe the adults, who say that Jumbo is eccentric but basically a decent person, maybe you'll think he couldn't have killed Jorge. If you believe Buck and Tunes you'll probably think there's no way Tunes could have killed Jorge. And if you think Tunes did kill Jorge, is it because you're like the white adults who say an African-American teenager is more likely to have done it than a white man who gives money to the library and is active in his church? These are questions I want readers to ask themselves when the book is finished.