I'm pretty sure your first statement is incorrect - he was merely a volunteer, he wasn't actually on duty. But that isn't entirely relevant to the situation.
As for your second statement, what we need is PROOF beyond a reasonable doubt that Trayvon did not attack Zimmerman because Zimmerman is the one on trial. We need proof beyond a reasonable doubt that what he is saying is incorrect. Right now all we have to go off of is the witness who saw Trayvon pounding Zimmerman's head into the pavement while Zimmerman yelled for help. That goes right along with his story.
This goes along with Zimmerman's story too.
Picture Of George Zimmerman's Head Three Minutes After He Shot Trayvon Martin

ABC News
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