I inserted evidence to support each hypothesis - just as life itself gives us contradictory evidence about a great many things. But in the end, it's all a mystery, insoluable, beyond certainty. Yet, the search of the cottage produces nothing incriminating. Both Claude and Ruth believe in Wade's innocence. And even Wade himself claims innocence toward the end of the novel.
Most novels adhere to a principle of certainty.
They show that this happened and then that happened. This book is different. This book is about uncertainty. This book adheres to the principle that much of what is important in the world can never be known. That's what disturbs people.