Here's my suspicion of how things went down.
Tray is walking along, heading back to the house is staying at.
CZ is driving along, armed, keeping an eye out for trouble in the gated community.
CZ spots Tray, an unfamiliar young AA male strolling through the darkness
CZ crawls along in the car trailing behind Tray
Tray senses his follower and surepticiously glances back trying to use his peripheral vision, possibly worried about being jumped, why else is someone rolling along slowy behind me, keeping pace. His hackles are now UP.
Finally, Tray turns and holds his arms wide palms up, probably defiant and cocky, hoping to scare off his unwanted stalker, and says "you got some kind of problem?!"
CZ then decides to confront this "suspicious" young man. He stops the car, steps out of the car and probably asks Tray who he is and what his business is in the neighborhood.
Tray, offended by this unknown person acting as if Tray has no right to be there, says something to the effect of "none of your damn business" or maybe "what's it to you?"
CZ then moves toward Tray, who is standing on the sidewalk.
Tray takes this as a threat of possible violence or attack coming his way. (as far as we know CZ is the agressor, at least in Tray's eyes) Tray decks the strange, confrontational man who is now coming towards him. They scuffle.
CZ pulls his weapon and shoots Tray.
I stick with my original opinion on this - CZ should not have been packing his gun, he should not have continued following Tray, per the 911 dispatcher's instructions, and lastly, he never should have confronted Tray.
From Tray's perpective, CZ could have been a threat.
From CZ's perspective, Tray was none. He was in a vehicle, he had reported his "suspicious" young AA male to authorities. There was no need for what came next. Zero.