It is clear who initiated the confrontation (i.e. Martin did not chase down Zimmermans vehicle on foot, and Zimmerman called the police while pursuing him before the confrontation began.) All that remains to determine is whether the confrontation and result were justified; it is hard to convincingly argue for either. Physically defending oneself from a strangers confrontation in ones own neighborhood is not "assault" (again, it is pretty much the basis of Stand Your Ground laws.) Conversely, shooting someone after picking and LOSING a fight is not "self defense," let alone justifiable homicide. That is not to say it is necessarily murder, and I agree the available evidence in this case made murder beyond a reasonable practically impossible to prove, but I also think a there is a very strong case for manslaughter.

Fact: Martin did not confront Zimmerman, Zimmerman confronted him.

Fact: That directly caused Martins death.

Those are not matters of interpretation, or suppositions needing witness corroboration: They are undisputed incontrovertible facts no world view can alter.

Incidentally, implications Zimmerman would would have chased down, fought, shot and killed a white kid walking home from the store in a nice neighorhood does not exactly exonerate him nor reassure me. The racial overtones here are far less serious than (because, IMHO, secondary to) the conceit civilian vigilantes merit the benefit of a doubt for killing innocent people. Zimmerman is not Bernard Goetz; Goetz defended himself from an unprovoked attack, and if the surviving attackers regret that defenses vigor the moral is "do not mug people." Zimmerman sought out, unprovoked, a kid who DIED for the "crime" of self defense; labeling self defense "assault" does not change that, only defy the very premise of Stand Your Ground laws.