Just read something else. In Florida, apparently, the police cannot arrest someone who asserts a self-defense claim unless they can prove the claim is without basis. If they do arrest someone who asserts such a claim
and that claim is later upheld in court, the police will be responsible for civil penalties, lost wages and other damages.
In light of that, Zimmerman's assertion that T. Martin attacked him, combined with the lack of evidence showing Zimmerman started the physical altercation and Zimmerman's injuries, the failure to arrest Zimmerman is consistent with the laws in place.
Statutes & Constitution :View Statutes : Online Sunshine
For those saying "Zimmerman should not have followed Martin after the dispatcher said it was unneccessary." Yup. Probably shouldn't have. However, while it may have been bad judgment, it was not illegal. Zimmerman had just as much right to walk (or run on) the public streets of his neighborhood as did Martin. [I live in a neighborhood that has had many break-ins and often observe young men walking down the street blatantly looking in car windows and testing car handles. I will go outside and follow them for a block or two and snap their picture on my phone to make sure they know people are watching. As long as I stay on public property, I am absolutely within my rights to do so].
It's a bad end with no real proof as to whether the use of deadly force was legally or illegally used. A tragedy all around with many lives unalterably ruined. It is not the first time such a thing has happened, and, unfortunately, it will not be the last.