I don't know if this will matter at all, but whenever I would leave my travel trailer unlocked, somehow some neighbor kids would know and they would get in it and check it out, open cabinets, jump on the beds, see if any water would come out of the faucet.
But what does puzzle me is how anyone could make a decision to abduct a small girl for sexual purposes knowing that he would have to kill her from a house not familiar to him? Even if there was a swinging session going on that would not reduce the risk of someone seeing him enter or leave or in the house.