I just saw a video clip shown on local news, the court arraignment of MM.
I have a large screen TV, sitting close to the screen, and there was a close up of MM, his head, neck, head, torso. Also saw him in profile as he turned his head to look at (I think) his attorney standing next to him.
Impressions:
1. MM is much larger than I thought. Very big man.
2. I did see the trembling you noticed, in the back of his neck shoulders. Very slight, but there.
3. Yes no expression on his face.
4. A guard behind MM asks him to move over a bit to make room for his attorney to stand next to him in front of the judge. MM doesn't hesitate, immediately moves over and appears cooperative, following directions.