Now that I am working in another city, I can only summarize what happen during the Zimmerman trial.
Basically, the Defense called everyone and their grandmother to testify that it was George Zimmerman who was screaming for help. Unless you can get Jesus himself to say it was Zimmerman, the biographies of these individuals will not matter. Everyone, the jury included, realizes all these people are biased. There is no way voice recognition would work. That is why you need to view the call in the context. If Zimmerman was screaming, then he was lying about being smothered? If Zimmerman was screaming, how did he get the composure to prevent Martin from reaching from the gun and fire a perfect shot into the heart? Why does the screaming end at the moment the shot is fired? Why would Zimmerman be screaming if he has a gun? The Defense is trying to get past this by having tons of people say it is Zimmerman, and then have Trayvon's father either say no or not be sure. You know something, people who are unsure are the ones I would believe.
Regardless, the Prosecution scored a huge victory today, that will go unnoticed in the media because of the obsession with who was screaming and marijuana. The Defense called Adam Pollock, the man who trained Zimmerman in MMA. Pollock clearly has an affinity for Zimmerman and I am sure he thought he was doing Zimmerman a favor by testified what a poor student he was. But, on cross, the Prosecution pretty much got Pollock to acknowledge that he was too poor. In fact, the Prosecution used Pollock to undermine a major component of Zimmerman's story - how he shot Martin. Pollock testified that only a skilled individual on his back and being mounted would be able to lock the arm of the person mounting him. And, Zimmerman most definitely was not skilled and if Zimmerman said he did that, Pollock would not believe him.
Guess who said he did that, George Zimmerman. Watch:
What amazing skill for the man who Pollock would only give a 1 on athleticism. BTW, this is why the Defense then put on Tracy Martin - but don't think the Prosecution did not catch that.
Also, we have the ridiculousness of ex-Stanford police chief, Bill Lee (who was fired for his incompetent handling of this case) who compared the voice recognition that everyone did as similar to a lineup and that the Martin family recognition was tainted because they did it as a group. He was shown to be a joke on cross. Bitter still.
A photo line up has a person look at 6 pictures and then pick one from there, if the person is there. A voice line up would require individuals to hear 6 different screams and then pick one. In this case, all parties involved heard one tape and were aware it was either Martin or Zimmerman. Doing it in a group would not taint it. Everyone is already biased. What a farce - he deserved to be fired!