Why is there any Question about Zimmerman?

The George Zimmerman trial resumed today in Florida and it is getting the usual big coverage from the media.  One has to wonder why.  The murder/manslaughter part of the trial is pretty much over already.  Zimmerman claims that he acted in self defense when he shot Trayvon Martin.  Legally, that means that the state of Florida has to prove beyond a reasonable doubt that when Zimmerman fired his gun he was not reasonably afraid that shooting was the only way to stop Martin from beating him further.  There is no way to do this based upon the evidence so far.  Zimmerman has already said in statements that he was being pummeled and feared for his life.  He also said that he shot Martin when the teen went for Zimmerman's gun.  The state put on a witness who lived right where the fight occurred and testified that he saw Martin on top of Zimmerman punching Zimmerman.  Then you have Zimmerman's injuries which are consistent with that story.  No reasonable man or woman could be certain or even close to certain that Zimmerman did not believe that shooting was the only way to end the beating.

There may be some lesser included offense that the jury could convict on, but murder and manslaughter are just out the window.  In fact, this has to be one of the weakest prosecution cases I have seen in a long time.  Zimmerman should never have been charged in the first place.