Well, there are several things that I think about this particular sequence of events and what Westerfield says and doesn't say when he talks to the police.
1) I don't find it odd that he would have his son check the house. Neal did, going in to actually put a flyer about Danielle in the kitchen. He said he left the house locked up.
2) DW tells the police he returns to the neighborhood after 3:30, talks to the neighbors, then goes to his house and decided to check the pool (fine) and then says the side door was unlocked. He hints "someone" (the cop asks if he thought maybe the little girl) could have gotten in his house. I think--is he setting up a reason any evidence in the house came to be there?
He further says that this (the "unlocked door") was a mistake but not unusual. I say, hmmmmmmm. Why isn't he telling the police about Neal locking the house, and why would a door supposedly be unlocked and DW says he doesn't intentionally leave the door unlocked but has in the past. See? Something is wrong here.
3) Calling his son to make sure the house is locked is the sign of a man who values security and, IMO, would be very unlikely to leave his MH unlocked while it was unattended during a long period of time. Long enough, say, for a neighbor to wander in and play.
Just my impression of that. John Jamieson thinks I'm analyzing it too much. I will be interested to see what Dusek says, if anything, about it in his closing argument.