Author Casey Cep writes about a true crime story Harper Lee could not complete. “Harper Lee always said that she was ‘intrigued with crime.’ She grew up surrounded by stacks of the magazine True Detective Mysteries, cut her teeth on Sherlock Holmes, watched trials from the balcony of the local courthouse as a kid, and studied criminal law at the University of Alabama.”

The story of Reverend Willie Maxwell, a man accused but not convicted of murdering and collecting death benefits from five family members, was as compelling as any story Lee had grown up with. But she could not pull it together. Perhaps the characters were too much larger than life.

Part of why true crime stories are so appealing is that they force us to confront the limits of what can be known, and eliding those limits, whether by fabricating motives or means or inventing someone’s inner life, doesn’t just cross the boundary between fiction and nonfiction; it transgresses something deeper.