As to the discussion of the bullet first theory...
I'm one who believes an ME and facts before a proven liar.
IIRC
-The ME testified that the throat slashing would have immediately and completely incompacitated TA.
-The gunshot would have incompacitated him very quickly and that it would have shocked his brain into not being coherant enough to defend himself.
-The knife into the chest would have taken a minute or so before TA was fully incompacitated.
IF shot first, I can't believe that TA could make it down the hall towards the bedroom and have had all those defensive wounds.
As per the ME, the bullet actually went through part of the frontal lobe of the brain, not that far but he believed it would have done some damage. I do agree however, that with the amount of decomposing it would be hard to say either way. But, I would tend to believe any gun shot anywhere to the head even not being fatal would stun you enough to not fight back.
I'm going with knife first until proven wrong
JMO.