I think even CSD would have a hard time justifying "Cop who's been drinking shoots an incapacitated, unarmed man laying facedown on the ground" but I've been wrong before.
$1 says he easily justifies it.
"He was laying facedown in order to get a superior tactical position, cleverly bleeding out to reduce law enforcement traction and then surprise attack if the cop didn't shoot him first in self-defense."
Come on now, guys. Is that the best you can do? I pride myself in knowing my opponent's positions before they can proffer them.
C&SD (should he think this is a good shoot) would begin by saying that we aren't getting the full story. (He's usually right about that. The only part where I sometimes disagree is whether the additional information does justify the officer's actions.)
He would then go on to post one or more other versions of the story from another point of view.
Now, having grown up in Illinois, and being familiar with the Chicago PD, I am fully willing to accept this story as it fits with my impressions of the "professionalism" of the Chicago police.