The article is a bunch of questionable and mostly irrelevant rubbish. Is that all they have wrt a picture of the gun? It doesn't even look like a gun.
The officer had expectations that he was the robber, was consequently in his mind, a violent person, especially as he was black, and overreacted to the percieved threat. A police officer should only shoot in self defence. This was not self defence as the suspect never actually drew the firearm. If I'm pointing a pistol at someone, with my finger on the trigger, I have enough time to fire before the suspect has enough time to reach for it, draw it and point it. Despite that, one shot in the centre of mass would have been enough to neutralize the threat, especially in the confines of a car. But he shot him 4 times. They somehow think that the suspect continues to be a threat while there is still movement. That movement is usually unvoluntary reaction to being shot.
It's the result of police in NA being militarized, and adopting the same rules of engagement as combat soldiers in warzones. The safeguard and protection of innocent citizens should be the first priority of LE officers, and that's why they're paid 3 times more than an infantry soldier. These suspects had the expectations of being innocent unless found guilty by a court of law.
That police officer was unsuited to be one, and should never be trusted with a firearm again.