Is it not true the Martin is dead? If he were alive, would his version agree with Zimmerman's. Where did I say all the witnesses are dead?

Just to be clear, you are using the term witness in a legal sense, I'm using it in a phenomenological sense, in that one who witnesses, which can include experiencing an event, which Martin, indeed, did. Fact is, no one, none of "the witnesses" fully witnessed what happened. All that can be done is to piece together all of the witnesses statements and see if the overall picture supports Zimmerman's version of the events. Sadly, their is not one for Martin.