I just can't see this as a teen or a drugged up person...no noise, apparently and no mess or fuss, i.e. too clean and quiet.
I am thinking someone who is escalating, i.e. has not done this serious of a crime before but has broken into, maybe, empty house and stolen items, that sort of thing. Or a peeping Tom who decided to take the little girl and the urge was overwhelming, which prevented him from being hesitant about the lights on, people home, etc...
I do wonder why, with the FBI involved for days now, they haven't issued a reward and sent out alerts nationwide in some way, add her to their website, etc...do they really have something that tells them this is NOT a kidnapping, other than suspicion? I do not believe LE is focusing on the family for lack of anything else to do. Perhaps the little experiments today were to rule out, officially, the idea of a person coming in a window, which may back up their theory if they also had no signs of unknown prints or DNA (I suppose they could have had quick turnaround on some results in a case of this nature-they had the DNA on Chelsea King's case almost within a day in CA).
There are just very few signs that the FBI or local LE is seeing this as a case where a child has been taken and could be anywhere in the USA or world, for that matter. They have the resources to issue BOLO's etc and don't seem to be doing so.
JMO