What I saw, and what was not seen as clearly as I would like.
At the start of the encounter an object seems to fall from the vicinity of the black male back towards the officer, in fact two items seem to come down, one black and one black and yellow. One of those objects seems to stay on the pathway, and one to fall into the grass just off of the pathway. What the object(s) were is very uncertain, but would be generally consistent with the size and coloration of a tazer.
The black male turns to flee. He takes several steps away from the officer who then levels his gun at the man. Audio is garbled but I, disturbingly, do not hear clear, authoritative, or multiple commands to halt, stop, get his hands up, he's under arrest, nor any other typical warnings. The Officer opens fire. It seems clear he misses the retreating man who is not presenting a then direct danger to the Officer. Around shot number 5 I begin to see evidence the fleeing man may be hit, his gait and posture change. By shot number 7 it is very evident the man is shot and stumbling. The man is now probably some 30 feet to 35 feet away from the Officer and obviously somewhat incapacitated. The Officer pauses briefly in his firing pattern, perhaps less then a second, but a very real pause, and then the Officer fires once more at the wounded man who is facing away from the Officer and not presenting any present danger. The black man drops down, possibly dead, certainly unresponsive as the Officer approaches giving commands to place his hands behind his back. (Now the Officer issues commands)
The Officer goes to cuff the downed man. As he does so it appears, for an instant, that perhaps the man has control of his own head and neck muscles. He seems to hold his head up briefly while being cuffed, though that may just be a result of the Officer pulling on his arm. This attracts my attention. Was the man still alive at this point, if only barely, and if so might the Officer have been wise to request medical assistance with greater apparent urgency.
Next I note that the second Officer arrives on scene more or less from the path of travel of the now deceased black man. It seems that the deceased was running right into a trap had the first Officer not shot him dead before he reached the trap. Also, it is possible that some of the missed shots were traveling more or less in the general direction of the second Officer.
At this juncture the first Officer walks back up the path to the site of the initial encounter we saw, although fairly clearly not the initial point of encounter. He stoops and picks up something off of the ground in the area where we saw something drop right at the beginning of the video scene. He returns to the body, now likely a corpse as we have not seen any movement or even muscle tension in some time, and he casually tosses whatever item was picked up, down next to the body.
From what I have seen the shooting was unjustified at its inception, and certainly by its conclusion. In addition to charging between reckless homicide to Murder 1, I note several violations of sound police tactics, and procedure.
In closing I note that the audio shows that before the shooting police sirens are closing in on the area. The Officer had reason to believe assistance was on the way. He was not out there alone. The cavalry was coming.