Just my ramblings and opinion/guesses here ...
I keep thinking of the psychological disorders that feature a lack of all empathy as one of their symptoms - AS certainly displays no empathy whatsoever throughout his horrible deeds in this case. I have it in my head that he just wanted to do this for the experience or thrill, and maybe notoriety or to prove something to others, without even considering any consequences - or at least thinking that he was too clever to be discovered.
I think his victim meant so little to him, and was objectified to such an extent, that he was probably very surprised at both the public's and LE's outcry and involvement in the search for Jessica, and then in turn hunt for him. He probably still thinks he is clever enough to outsmart the courts too.
:moo:
And yes I am not getting the connection between the catdoor/vent or any other surmising about the layout of the house. I think LE probably know where the relevant crime scenes are, or wouldn't we be aware of ongoing searches at other sites? To me it doesn't seem important whether it happened in his basement/bedroom/bathroom/garage - AS obviously had the privacy and time he needed - it wouldn't be unusual for him to have his own room or part of the house that was considered his "man cave" that his family would have stayed away from. My own younger teen doesn't want me in his room most of the time because he knows I will just start nagging about the mess - so I actually don't venture in too often.
OK really rambling now, so will leave it there ...