Well, he was shot over a dozen times at close range (probably while sitting with hands up), and both palms had exit wounds.
I’m not sure how well visual inspection would work with all the blood and other carnage.
However, I’m also not sure if trace gunshot residue will show up on current forensics tests if multiple people empty their clips into you from a few feet away.
There’s also the question of why they shot him over a dozen times while he was unarmed.