I agree it is not the best interview...and also the media can sway things by how they present things...camera angles, what they edit or don't edit etc. I have seen that countless times when a story is about something that I know more about or the people involved.
Aside from this we shouldn't forget that there could have been other factors at play like lack of sleep, effects of possible medications post car crash or for anxiety/ depression in relation to the events that could have effected his responses and body language etc. It wasn't a formal press release. He obviously wasn't that keen to speak either. I am sure that we all have days when we are more communicative and presentable than other days. Stress can have a big effect of people....and yes he could be stressed because he had done the deed......or he could just be stressed because Allison was missing, he'd crashed his car, compounded by all of his financial/ business/ relational issues regardless of whether he committed the crime or not. We can't label someone as a sociopath or whatever other disorder based on one brief interview.
I respect your opinion but to me regardless of the circumstances or influences, a normal relative of a missing person would still ask for help finding them, plead for their return or at least asked them to come home, call and say they're ok something. We got none of that which is a huge red flag for me...The only reason I can thing of for him not doing this is that he knows she ain't coming back! Geese I lost my son at the shop the other day and I was asking everyone around the shop if they had seen him telling them what he was wearing, what he looks like, how tall etc...or maybe I'm the one with the strange behaviour :what: