On Clint Eastwood's "Changeling" and Gruesome Murder Stories

So being the father of a two-year-old, it took me a while to watch the based-on-a-true-story Changeling (2008)—a star turn for Angelina Jolie (whom I sympathize with; she seems like a kind mom, even if she is a Hollywood brat, perhaps grown wiser now), and another stunner directed by Clint Eastwood. Imdb.com has some great details about this, including that most of the film is true to life, although it’s hard to ever trust Hollywood. The writer, J. Michael Straczynski, supposedly wrote the screenplay in seven days, after months of research on the real-life Wineville Chicken Coop Murders. I can believe it. The story is riveting and dense with odd details that work best because it’s based on an actual event. I immediately wanted to know how much of the story was accurate. It seems that much of it was. A great example of the power of fiction vs. nonfiction. If it was all fictionalized, I don’t think it would be as good a film or story. When Jolie’s character is placed in a psychopathic ward by the police, that would seem too rhetorical (message = bad police) if it had not happened.
As a novelist, I pay attention to the patterns of classic stories/novels/films, and have sometimes squirmed against the preponderance of murder plots. It’s the ultimate sin, perhaps, the ultimate bitter end. I admire the storyteller who can avoid murder plots and write a great book. Anna Karenina and Madame Bovary come to mind, but since both feature suicides, that’s a squishy distinction—suicide is self-murder. Lolita is a classic murder story, although the heart of the story is not the murder, but Humbert’s forbidden love. I’ve written about Out Stealing Horses as one of my favorite recent novels, and it has an accidental death in it, an accidental murder.
Now I know that the definition of murder implies a deliberate, not accidental, killing. So technically when Lars kills Odd in Out Stealing Horses, it’s not murder. But still. It’s an Unnatural Death. Perhaps that’s what novels seem to feature most often, The Unnatural Death. Why?
The simple answer: it ups the ante. An easy question for storytelling is: What’s at stake? With a murder, it’s all. What more can you lose?