No, there are levels of reliability.
I suspect you will propose only those witnesses that agree with you are reliable.
I don’t know how you can conclude the shooting is self-defense without knowing how it started.
We have the police investigation.
We know Zimmerman was headed for his car, that would be a direction AWAY from Martin.
We are left with a couple of possibilities how their paths would have crossed again.
Either Martin turned around and followed Zimmerman…or Martin doubled back and around.
Either way, it is now Martin, and not Zimmerman, that is following.
We also have the grass stains on the back of Zimmerman’s clothing that tells us he was violently thrown down on his back.
We have the broken nose and other bruising on his face, telling us that he was hit multiple times in the face.
We have lacerations on the back of Zimmerman’s head indicating that it was slammed multiple times into the concrete.
We also have an autopsy that shows Martin had no wounds one would associate with a fist fight other than bruising on his knuckles. Telling us that Zimmerman was not fighting back or was ineffective in fighting back.
All of the evidence indicates Zimmerman was violently attacked. This alone justifies the self defense shot that was fired.
The verdict from the jury likewise supports this conclusion.