If I were scripting the Drew Peterson saga, his arrest wouldn't be the big dramatic moment. The BDM would come when he's convicted, at which point his fourth wife would come out of hiding. It would then be revealed that she faked her own death after he told her that he'd killed his previous wife and gotten away with it, and threatened to do the same to her. So she went into hiding leaving just enough evidence to get the cops interested.
Unfortunately, life very rarely works like that.