And I, for one, think that the fact that she left wearing her pajamas is one of the factors that led them to conclude that she wasn't a runaway.
I do think, though, that maybe whoever led her out of that house said something to her that lulled her into a false sense of security. Perhaps that false sense of security ended about the time the neighbors heard that "shout."
The fact that she has not resurfaced, apparently not even a trace of her, tells us that no matter how she left that house, she's probably been the victim of foul play. So really it wouldn't matter even if she had run away, the end result is the same.
I'm sure suicide has long ago been ruled out, too, since as we heard often in the Chandra investigation, a suicide cannot bury his/her own body.
Sandude said a while back that the police have probably said something to the Smarts that has helped them realize that Elizabeth is almost surely no longer with us. That's true, but I remember that the Smarts were, just a short time ago, all fired up about finding that pig-roast guy--even though they clearly thought that he had maybe been digging a GRAVE. I think--I hope--that the Smarts will keep on trying until they at least find out what happened. After that, they may lose interest, as did the poor Levys, and I wouldn't blame them. Though it's also important to find out who committed the crime, I'd think that finally finding their loved one's dead body would send anyone into a downward spiral for quite some time.
That dog will hunt. Might not find anything, but it will hunt.