My next comments may spoil, even though it is speculation on the conclusion of this case. So, if you don't want to read it, that's fine. haha, but this is just my take based on what I saw.
So, I had been thinking about it, but based on the flashbacks compiled in my head from Sophia and the conclusion Grissom came to about "not-so friendly fire" with Doc Robbins, the angles are all off.
In Sophia's flashback, she is behind Bell and firing. She says the officers were in front of her and to her LEFT. We see the path of one of her bullets which is to Bell's RIGHT and above his head. Then Bell rises, more gunfire and he goes down. Now there, it looks like Sophia may have been responsible, but. . .
In Grissom's analysis, we see the bullet enter from Bell's left and exit out the right side of his neck. In his words, "Left to Right, Back to Front. Only cops were shooting in the direction." Well, technically, yes...but not Sophia.
Now if I put those two images together (without mixing up my lefty and righties) since she was behind Bell (with Bell to her left) she was firing from his right to left, then Sophia's bullet really should have entered from the RIGHT and not the LEFT as in Grissom's analyisis.
Haha, that was probably really confusing.
But that's what I really think. I don't think Sophia is responsible for Bell's death.