A novel about a crime or a crime novel?: The Round House

I don't know how well Louise Erdrich's The Round House stands up as a crime novel - though the central event is an attack on the narrator's mother and his attempt to find out who attacked her and why - but I am coming to think that the solution to the crime is not the point - the narrator's (he's a 13-year-old boy) search for the evil-doer is a narrative vehicle that drives us through the novel; as he looks at one suspect after another, we meet a number of different odd, outsider personalities on the Indian reservation and, perhaps, if the novel really clicks at the end, their stories will enmesh and affect one another and build from elements into a greater whole. First two suspects that he pursues are a Catholic priest whom, for some reason, he'd overheard his father discussing as a likely suspect, I can't remember why - Joe and two friends follow the priest home and spy on him (no doubt the priest has detected them outside his window), and, when the priest strips in front of his window and they see how physically maligned he is - wounds from the Beirut embassy bombing, they later learn - Joe realizes he could not have raped his mother. This investigation thought remotely possible I guess does strain credulity; and I can't quite figure out why at some points Joe's father, a judge, very dramatically tells him to drop it, to not pursue the facts of the case - but then draws him into his own investigations of the crime. The second possible perp - or at least possible source of information about the crime - is one of the very few white women who'd been adopted by an Indian family and raised on the reservation. Most of this section is her narration of her life story - again, an interest piece in the mosaic, but wandering off the course of the plot. Erdrich is such a strong writer and her material is so abundant and unusual that it's a pleasure to follow her on her tangents, but I am hopeful that she will keep the novel taut and dramatic and not let the strands unravel.