Antwon Rose, tragic but....Over on Reddit I found this checklist of justifications for the use of deadly force by law enforcement. In other words if all factors apply, deadly force is warranted.
(1) the person to be arrested has committed a forcible felony
(2) he’s attempting to escape and possesses a deadly weapon
(3) he will endanger others if not arrested right away.
Here's a well-reasoned analysis of the situation.
In these situations police have to deal with uncertainties. The car matches the description of a vehicle involved in a shooting, it has bullet holes in its rear window. The suspects flee and the officer has no idea whether they are armed or not, but he has very good reason to believe they are (ie. the shot up car). No certainty but objectively speaking a high probability. He has to decide is it better to let this guy escape on foot and potentially take a hostage, kill someone who gets in his way or shoot at another cop trying to detain him. Remember he doesn't KNOW this guy is unarmed, he only knows that there's a good chance he is. In retrospect you can say hey he was fleeing and unarmed, but given the circumstances in the moment the cop is very justified in believing him to be armed and dangerous to the public. If anyone is ever in that situation it would be a huge mistake to run.
LINK:
https://www.reddit.com/r/pittsburgh/comments/8srsuk/antwon_rose_tragic_but/