For more detail, the killing is reported here: Orlando Watch Shooting Probe Reveals Questionable Police Conduct.
So, a white neighborhood watch vigilante kills an unarmed black teenager, and walks free claiming "self-defense". The vigilante was instructed by 911 dispatchers not to confront the boy, as officers were en route.
This is murder, clear and simple.
Now, let's do a thought experiment. What would be the fate of the killer if he'd been a black man and the victim a white, unarmed teenager?
Add to the list of capital crimes for blacks "walking while black".
The killer, George Zimmerman, needs be arrested and charged with 1st degree murder. If not, it seems that there is an open season on the sport killing of black people. All a white person has to do is claim "self defense" and move on to the next victim.