New here. This case has intrigued me.
A few thoughts I have had that I haven't seen mentioned:
1. Is is possible that the dog just got out of the house during whatever was going on and ran off? I don't know much about dogs, but seems like some will get out and be gone for several days. I am hoping that maybe he/she just ran off and may be found in a few days.
2. Where was HIS car during all of this? I keep thinking that maybe his car was as the house (in the garage?) at the beginning of this and that he may have put Sarah in the trunk and left her there, instead of taking her all the way back to his house, while he took care of everyone else. Or that he ordered her to go and get in the truck or car under threat of hurting the family if she didn't. I seem to recall that is basically what happened to the Groene kids. Then he was able to control them by the fact that he had "control" of Sarah. Just something about the words used like "she was under his control" and "didn't leave of their own volition" and/or "under their own power".
3. Where was the mom during that day? Is it possible that somehow he was stalking her/them, she was near the university where the truck was found, he flagged her down for a ride home with some story (leaving his car in the area). She may have recognized him as the son of a neighbor and then they/he could have had a few beers at the house being social, until kids came home and whatever else happened. This would explain leaving her car on campus, he would have transferred to his car and driven home where he had already left Sarah. If they were hanging out then maybe mom mentioned that boyfriend wasn't going to be home that day and he saw an opportunity?
For those speculating how he got them under control, all he had to do was grab one of the children (probably Sarah). If he was in the house in a social way in an instant he could grab her, with a weapon or not, and be in complete control of the situation.
I really hope that it doesn't end up that any of them were in that house on Wed night when the police went by. That would be absolutely heartbreaking.
Going back to lurkdom now. Thanks for all the great information and great forum.