I concur. We need more information.
The incident lasted how long, 10 minutes? (Don’t repeat, I haven’t checked to verify!) And what have we got for evidence? The 911 call recordings, Mr Zimmerman’s statement, one eyewitness, “John”, to a few seconds of the fight on the grass, two or more witnesses who heard the screams for help, Martin’s girlfriend’s statement, and the police report of the scene AFTER the fact. That is all. Background information about the principals is no evidence.