several reasons that Zimmerman was found innocent.
first of all, he was on the neighborhood watch group and there had been burglaries in that neighborhood, and Martin's actions may have been suspicious to Zimmerman. and he did call it in and they LE on the way. the phone was still on and 911 dispatch did record it during the scuffle. okay let's address this. had Zimmerman provoked Martin into attacking him an then shot him, a reasonable person could assume that call to 911 would have been after the shooting, not before. if someone is out and about at an odd hour dressed in dark clothing, similiar to what a potential thief might wear, when there have already been a rash of burglaries, wouldn't a reasonable person be inclined to be suspicious? i would be.
it was several weeks before Zimmerman was arrested and the former police chief Bill Lee was terminated or resigned because he felt there wasn't the evidence to support a case of murder and the facts bore out Zimmermans account of the events. there was only an arrest after all the pressure from the media and after Chief Lee was fired or resigned.
this was tragic set of events that left a young man dead, and another man on trial for that death. if Zimmerman has any conscience, this will eat at him for the rest of his life, even if he acted in self defence. a normal person can't take the life of another person, even if that other person was vicious and evil and not have it change their life. i saw that change in friend of mine many years ago. he was a couple years younger than me and had joined the PD in the town i lived in. he had only been with the PD for few years when one night he shot another young man who was intoxicated at a party and had cut another person with a knife and was threatening my friend with the knife when they arrived at the scene. Jimmy told the young man repeatedly to drop the knife, but instead he advanced and my friend shot him three times, killing him. Jimmy was no longer the same person. he was withdrawn and depressed. he began drinking, ended up divorced and then shortly after that he resigned the PD. it was a justified shooting that left one young man dead, and other young man destroyed and destroyed his family in the process.