SOI3 was in his uniform. Maybe he only burned his jacket and not his pants. Though there should have been no reason he had blood on him if the affidavit is to be believed.
Didn't I2 testify that I3 threw the woman to the floor?
I think there is a lot more to the story. Remember this was just an affidavit to go after SG. I am sure they limited what they put in about a lot of the details about the other guys behavior.