My thinking on this is that you're reading your own biases into this story big-time.
I don't know where you get off insinuating that a person has no right to follow a suspicious person. And it has turned out that Martin is no angel, was a pot smoker (which can be very expensive) and had been suspended for possession of burglary tools. Dots to connect if you are so inclined that Martin may very well have been doing something other than innocently walking home from the 7-11.
There is no evidence that Zimmerman did anything illegal or improper in this episode. And the thug culture mindset that Martin clearly had started to embrace is entirely consistent with Zimmerman's version of Martin confronting Zimmerman for following him - and then attacking him for no good or legal reason.
So yeah, we can't get Martin's version of events or close all the gaps with irrefutable evidence. But we have data points to weigh Zimmerman's story. And ALL the points so far back his version of events. The only reason he is charged is political cowardice and expediency, because the evidence gets nowhere near a civil preponderence standard, let alone beyond a reasonable doubt.
A pretty sorry statement of the position the prosecutors (and you) are taking here - that Zimmerman bears any kind of culpability for what happened. And if I were you, I would take pause in the fact that you are on the same side as the folks on the left braying for changes to Stand Your Ground and self-defense legal rights.
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There is no evidence that Martin did anything illegal or improper in this episode.