There is a very telling part in the call when the dispatcher asks for his address, and Zimmerman states he doesn’t want to give that info because, “I don’t know where this kid is”. If at that point in the tape,after Martin ran and the dispatcher told Zimmerman to go back to the truck to meet the police, he obviously could not have been chasing Martin.
I have to be honest - I don't have a clue who started the confrontation, but, like you, I listened to Zimmerman's whole 911 call, and I was also struck by this part. Not only does he not know where "this kid" is, but he seems a little nervous - not like the aggressive pursuer you might expect (from the simple fact that he got out of his car after noting that the person looked like trouble.) He doesn't want to say his address in case the kid is close enough to hear him - he definitely sounds nervous.
A lot has been made of the 911 operator suggesting that Zimmerman should not pursue, but he does say, "okay" in response. We can't see what he is doing. I suspect he was still following, but at what he thought was a distance. The kid was hurrying away, but with a watchful eye over his shoulder. At some point, I am guessing, they may have found themselves suddenly in closer proximity than either expected. Remember, Zimmerman had lost sight of Martin. Martin told his girlfriend he was hurrying to get out of Zimmerman's sight.
But somehow, they ended up face to face, and at that point the whole "why are you here?" "why are you following me?" conversation occurred. Both of them scared. Neither wanting to back away (or turn his back.)
Then what?
I don't think we will ever know. But I do think that it is not as cut and dried as so many seem to think (including me, when I first started reading about it.)
Was Zimmerman "aggressively pursuing" or just trying to stay close enough to keep an eye on Martin?
Was Martin trying to get away, or trying to assert himself? Somewhere in the dim recesses of my memory, I can recall being a teenage boy, and not wanting to appear frightened. It happens. Was it Martin who suddenly stepped out of the shadows to ask "why are you following me?"
And not to spread the second-guessing too far beyond Zimmerman and Martin, but when two guys are fighting, and one is screaming for help, didn't anybody even come outside and yell "stop it! I'm calling the cops!" Because that may very well have stopped the fight.
This was a real, senseless tragedy. And I'm really only sure of two things: Trayvon Martin is dead. George Zimmerman is going to do some time.
You can decide for yourself if either one of them deserves it. It's hard for me to think of any reason Martin deserves to be dead, but I'm getting a lot closer to concluding that neither one of them deserves his fate.