(CNN) -- On the basis of the evidence currently in the public record, one likely outcome of the case against George Zimmerman is a mixed one: There may be sufficient evidence for a reasonable prosecutor to indict him for manslaughter, but there may also be doubt sufficient for a reasonable jury to acquit him. 

Any such predictions should be accepted with an abundance of caution, however, because the evidence known to the special prosecutor, but not to the public, may paint a different picture. It may be stronger or weaker. 

Media reports suggest that police found Zimmerman with grass stains on the back of his shirt, bloody bruises on the back of his head and other indicia that may support his contention that Trayvon Martin was banging his head against the ground when Zimmerman shot him. 

We don't know what Martin's body or clothing show, other than the fatal bullet wound. If there are no comparable bruises or grass stains and if the bullet wound and powder residue establish that the gun was fired at very close range, this too might support a claim of self-defense. 

Then there is a recorded cry for help, which, if it turns out to be the voice of Martin, would undercut the defense -- if the voice analysis passes scientific muster and is deemed admissible into evidence. 

There may be additional forensic evidence -- or witnesses -- of which we are now unaware, though it is unlikely there is a "smoking gun." 

Finally, there is the overarching and historically painful reality that an unarmed black teenager lies dead at the hand of an armed Hispanic man who ignored a dispatcher's advice not to follow and engage the "suspect," and who may have -- and this too is forensically unclear -- uttered a racial epithet while chasing him. 
Do we know who's cry it is?
Then there is a recorded cry for help, which, if it turns out to be the voice of Martin, would undercut the defense -- if the voice analysis passes scientific muster and is deemed admissible into evidence. 