We're thrilled bombshell on the eve of the racially and emotionally charged murder trial of George Zimmermann a big win for the defendant even before tomorrow's opening statement and judge ruling... See More
We're thrilled bombshell on the eve of the racially and emotionally charged murder trial of George Zimmermann a big win for the defendant even before tomorrow's opening statement and judge ruling audio excerpt experts can't testify about the most dramatic evidence in the case. And I -- reporting and Zimmerman deadly encounter with -- on Martin's. Here's ABC's Geovany test with the story good morning to you now. Good morning to you beyond -- this is exactly how Zimmerman defense team wants that the State's audio experts have said it's Martin's voice on that tape the defense slows its government. Now jurors will have to decide for themselves. This morning prosecutors charging George Zimmerman with second degree murder. May have a harder time proving who's screaming for help in that 911 call. Yeah. Yeah yeah. Did Zimmerman fear for his life and -- -- -- -- in self defense. Or was that Morton's voice the prosecution's voice experts say it's the seventeen year old but -- defense team has challenged their science. Now so was the judge riding in a ruling there is no evidence to establish that their scientific techniques have been tested and found reliable. The fact that the prosecution cannot present their voice recognition experts. In this trial is a victory for the defense because a judge is now allowing those jurors to listen to the tape and decide for themselves. Who they believed to individual screaming out for help kids. Even though the two sides have battled it out in court. It is not unusual or find -- -- -- different -- sorry I don't follow the difference the tale of the tape has been a complicated one to tell. V pivotal issue in this case is who the aggressor was on -- all night and that 911 tape tells the story. Analyzing the tape is no easy feat and some suggest even impossible a voice analysts ABC news brought the recording to. Said he couldn't be sure whose voice is on that tape. Because the recording is -- clear and off their standards for boards fabrication and that this case doesn't match. And even though the State's audio experts can't weigh in there's no doubt that 911 call will be a central piece of evidence in this trial and that begins tomorrow with those opening -- guys and still -- a big win for the defense and as you said opening statements tomorrow will be all over this story GO thank you.
This transcript has been automatically generated and may not be 100% accurate.