I think that's a fair question, albeit a sensitive one, and my thoughts will also be in the "sensitive" realm, so for those who are upset by this sort of thing, stop reading now. The following is JMO, MOO.
Based on the evidence we've heard from TS who reportedly said he was "pooping his pants," I would hazard a guess that she hurt him internally on Sunday -- an internal abdominal injury that affected his bowel and the poop may have been bloody. If LE discovered residue of blood with fecal matter, they might have assumed GS could not survive that sort of injury without medical help.
I also think the bloody board TS mentioned was out in a field could indicate she took him somewhere and beat him severely enough to perhaps leave brain matter on the board, which would also indicate he couldn't have survived his injuries.
There is also a possibility that she went back and moved the body on Monday when she had the rental car. If she did that -- but a cadaver dog hit on the original spot where the body was -- LE could have tested dirt, snow, etc., and might have found GS' DNA there, and I think they can tell if residue, etc., is from a deceased body, because there is already evidence of decomposition, somehow.
Those would be my first three guesses -- but like everyone else here -- they are just guesses based on the evidence we're hearing.
I'd like to hear what others may think.
I’ll be in & out AGAIN
