Your post made me think...8 people in a small house. Would any of the kids really have anything that would have their scent only? I imagine most toys, clothes, bedding, etc were shared, possibly with the exception of toothbrushes. And even that, I can see toddlers just grabbing one, I know mine did on occasion. I’d really like to know how long the other kids were with grandma AND what was in the West’s laundry basket and trash can. There should have been either yesterday’s clothes/underwear or fresh dirty diapers/pull-ups in the trash. That would be the most telling clue to me.