Editor's note: Alan Dershowitz is the Felix Frankfurter professor of law at Harvard Law School.
(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.
These "facts" give rise to several possible scenarios of what may actually have occurred on that dark rainy night. Under the Florida self-defense statute, it matters greatly what happened, most especially who "initially provoke[d] the use of force," and who started the physical encounter.
If Zimmerman initially provoked the deadly encounter, then he cannot invoke any "stand your ground" defense. He would then be under a legal obligation to "exhaust ... every reasonable means to escape."
Though this statute is anything but a model of clarity, it does suggest that whoever "provokes" a deadly encounter has a heavy burden of justification in claiming self-defense. But the statute doesn't define "provokes," and that ambiguous word may hold the key to the outcome of this tragic case.
If provocation is limited to a physical assault, and if Zimmerman's account that Martin blindsided him with a punch is believed, then Zimmerman did not provoke the encounter. But if provocation includes following the victim and harassing him, then Zimmerman may well qualify as a provocateur. Moreover, a jury may believe that Zimmerman started the physical confrontation by grabbing Martin. This would almost certainly constitute provocation.
But to complicate matters further, even a provocateur has the legal right to defend himself under Florida law if he can't escape and if he is in imminent danger of death or great bodily harm, as Zimmerman claims he was.
All this goes to show how factually driven this case is under Florida law. And we don't yet know all the facts. The special prosecutor, who has said she will not use a grand jury to decide whether to indict Zimmerman, has an obligation to consider all the evidence and to apply the law to the facts.
All she needs in order to indict is probable cause that a crime has been committed. A jury that ultimately decides whether the defendant is guilty needs much more: proof beyond a reasonable doubt. But what if a prosecutor concludes that there is both probable cause and a reasonable doubt?
That is the nightmare scenario that this prosecutor may well face. In ordinary circumstances, most prosecutors would not bring such a case, because it would be a waste of resources to indict someone who will probably be acquitted. But this is anything but a run-of-the-mill case.
Moreover, the Florida statute provides an additional layer of protection to a defendant claiming self-defense: A judge must decide whether the defendant is "immune from prosecution," that is, if the judge believes his actions fall under the law of self-defense.
So the following mixed outcome is certainly possible: The special prosecutor indicts; the judge does or doesn't grant immunity; if he doesn't, the jury acquits.
Many people would be unhappy with such a mixed outcome, but it is not the job of the law to make people happy.
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The opinions expressed in this commentary are solely those of Alan Dershowitz.