I honestly believe that the SW was served because they discovered he lied to them and a lie on the day of the murders, along with the bodies being found on his property, provided probable cause. The rest is details.
And my guess is that the reason he's not ruled out is simply because if it's correct that they really don't know who did this (I think that's the case), they're not officially ruling anyone out.
As for the demeanor of LE in the video up thread, he struck me as pained by the fact that they have not solved this and BG is still loose somewhere. I didn't see much more in his expression than battle fatigue and perhaps some low morale, which I'm sure they all feel, at least at times. I think the crime scene was disturbing not merely because they found children from their community, but because of the nature of the crime.
I go back to what LE said in the early stages - "who's next?" (I think that's how it was worded). That says a lot and points away from RL. I really don't think his type of lie, though they had to pursue a search, equals a connection to the type if crime scene they encountered. So, the demeanor we see in LE is perhaps also their pattern of not really saying anything of substance in public.
I had a son in naval special warfare and they don't talk about anything because once you say this, it leads to a question about that, and if you answer even vaguely, that leads to a question about this, and before it's done, you've provided tidbits that may not give up anything vital, but they feed speculation and rumor and interpretation of what people want to find in your answer. So you get emails that say, "Goin' on a trip", then nothing for three months, then an email that says "Back from my trip", and you know it's time to send cookies again. As they say in the Navy, "those who are talking don't know, and those who know aren't talking."
I think LE is coming from exactly that place in this case. I don't believe that their snippets and on camera language tell us much of anything. JMO