How does the novel being written in a first person narrative make it ethically challenging for the reader?
Well, the reader tends to take the side of both the narrator and Lou Ford in the novel, with him being very convincing in how he tells his side of the story, along with the explanation for his behavior (which seems reasonable from his point of view). The novel leaves the reader to choose whether to deny his logic or not, along with how they choose to judge Lou in his story. On top of that, the ending of the novel seems to indicate to the reader that the story is being told by a man who is already dead.
The novel The Killer Inside Me by Jim Thompson is one of those novels in which the reader is both fascinated and horrified. The challenge to a reader's ethics is clearly outlined in the casual violence and the corruption evident in the small town and its sheriff while the use of first person narrative makes the reader feel as if inside the mind of the killer. Thompson is challenging the reader to judge Lou Ford as a man and a psychopath living and killing in a small town. The ending shows the results for Lou which is death, but what about the rest of the town which seems to accept corruption or the reader who wants to judge Lou Ford with less than honest ethics? Is Thompson correct that potentially there is a killer in all of us? I think not and the ending is the proof.