Crusader's Cross question

Anyone else find this book's ending to be indecipherable? I love Burke's writings- the characters, the atmosphere, his descriptions of rural Louisiana. But his endings are often ambiguous and confusing, and this one was no exception. I have a vague idea of who the serial killer was, but that seemed to come from nowhere. And I have no clue how the other characters fit in or what their motives were.

Burke seems too good a writer to write something that makes no sense, so I suspect it's all on me and my lack of attention to details.