Sure it could be he is nervous, etc., but any way you look at it, his giggles are very inappropriate for the situation. It makes people confused and uncomfortable.
He said he wants to appear natural and he wanted to keep going with the interview because he wanted to "get the word out there". He might have been sincere because he kept trying to do the interview. Not much info he gave was clear on timeline, some parts changed at times, and his answers started to seem evasive to me.
However, I'm not sure the giggling points to his guilt.
If he did something
ugly to harm them, it seems his face would reveal it and he would not be able to laugh. Doing something to harm that little baby?...I don't know, sometimes he does cry with wet tears, but that could be his sincere fear for their safety. Just trying to read what we're seeing, and not quite understanding his behavior.
I initially noticed and got nervous about his soothing rocking back and forth sway like CW, and his putting his hands up near his eyes and forehead often, and looking down a lot, closing his eyes and smiling as tho' remembering endearing moments. There's lots of body language and non verbal (maybe) tells, but I'm just one of the people he got the word out to and
I'm not sure what the word is saying.
ALL JMO