Thoughts on, and a place to discuss, the plot details we can't reveal in our review.
Okay, so a third of the way into the film, it became screamingly evident that the kidnapper is Wes Bentley, the cop so creepy that his boss basically tells him to fuck off and go become a firefighter. He’s new to the force, he seems strangely obsessed with Seyfried, he keeps trying to get in her good graces and get her to come turn herself in to him personally. The vague glimpses of the kidnapper we see look like him. He disappears with a really lame excuse (bringing soup to his sick mom) when Seyfried heads off to meet the kidnapper. And he has, as that ever-so-Portlandian skateboarder puts it, rapey eyes. So I was mildly impressed when the kidnapper turns out to be a) not the most obvious guy in the film, and more importantly, b) not a ridiculously unlikely character we’ve already seen, like the lady detective with the terrible hair, or seeming single-mother-of-two Jennifer Carpenter (Deb from Dexter). Red herrings are common enough for films like this, but it’s reasonably daring to have the killer turn out to be someone who’s just as random and unknown to the audience as he would be to the onscreen victim.
That said, the ending pretty clearly indicates that Seyfried is off her nut. And it’s hard to blame her, given what she’s been through earlier in her life, and throughout the movie. And there’s nothing particularly wrong with that as an ending for the movie; when she tells the cops “Nothing happened, it was all in my head” and slams the door on them, it’s a fairly emotionally satisfying coda. But then why have the second ending, where she sends the authorities a map to lead them to evidence that she murdered someone? Evidence that without her intervention, they clearly aren’t going to be looking for, and might never find? Maybe she is too crazy to be running around free.