Arresting the person responsible for killing an UNarmed teenager (after being told in the 911 call, we don't need you doing that (following), is NOT a 'presumption'.
They had a UNarmed dead 17 yr old.
If Zimmerman stayed in his car, with his gun, Trayvon would be alive & Zimmerman would be free.
That was Zimmerman's decision.
Now we will have a trial (as long as 'Stand your ground' doesn't meet the law in this case) otherwise a judge could throw this out before trial.
Your inflammatory hyperbolic language is inappropriate.