George Zimmerman Murder Trial: Analyzing Those Screams for Help
(SANFORD, Fla.) -- It's one of the biggest mysteries in the Trayvon Martin-George Zimmerman saga: Who is screaming for help in those 911 calls placed by neighbors reporting a fight that was stopped by a bullet?
ABC News has exclusively obtained a sample of Martin's voice. That audio, which both prosecution and defense possess, could be a pivotal piece of evidence once the trial starts.
The sound could help forensic audio analysts determine who was overheard howling for help in the 911 calls that night.
If the howls are Zimmerman's, it would support his claim of self defense. If they're Martin's, it would significantly weaken Zimmerman's assertion that he felt his life was in jeopardy when he shot the unarmed teen to death.
ABC News sent the short sample, gathered as evidence from Martin's cellphone, to a forensic analyst. Kent Gibson, of Forensic Audio, tells ABC News a comparison of Martin's voice, Zimmerman's voice and the screams on the 911 tape, indicate the voice is more likely to be Zimmerman than Martin by a significant margin.
However, he adds, so much of the howling and pleading overheard on that 911 tape is muffled or obscured, that only two seconds of the tape are useable. Therefore, he says, there can be no definitive identification of "the screamer."
The FBI's leading forensic audio expert said much of the same in his testimony Thursday. Dr. Horotaka Nakasone called it "disturbing" that someone would be able to make a positive voice identification based on the screams.
Both families contend that it was their loved one crying for help more than a dozen times.
On Friday, in the final hearing before Zimmerman's second degree murder trial for Martin's death begins on Monday with jury selection, Judge Debra Nelson could rule on how the teams of lawyers might present those 911 calls to a jury.
One expert, whose testimony was recently submitted as evidence by the state, claims he can hear Martin saying "I'm begging you" just before he is shot and killed. Another expert says some of the screams came from Martin and others claim it is Zimmerman.
To ID the screaming voice, forensic audio experts required samples of both Zimmerman's and Martin's voices. But no audio of Martin's voice had ever been released to the public until now. ABC News has obtained audio of Martin laughing and talking about two men arguing over a bike.
During testimony Thursday, Zimmerman looked down at his lap as the 911 call was played in court for Nakasone, the FBI voice examiner who had worked on the case.
Nakasone testified that dissecting the 40-second 911 sample and figuring out who exactly screamed couldn't be done because only three seconds were unobscured.
"[The sample] has to be at least 16 seconds long," said Nakasone. "American English has 44 different sounds. To cover all those it takes 20 to 30 seconds."
This final hearing before the trial was called for by the Zimmerman defense, arguing that the science involving picking out certain audio is inadmissible or is so new that it shouldn't be allowed by a jury.
The state contends that its audio experts are credible, and that it should be up to a jury to decide what to believe.
Shawn Vincent, a spokesman for Zimmerman's lawyer Mark O'Mara, told ABC News, "That 911 call will get played in court. It is an important piece of evidence that will be played for the jury to make up their mind."
"The 911 call is probably the best evidence of what happened that night besides George Zimmerman's testimony and Trayvon's," said legal analyst Bill Schaefer, who noted Martin wouldn't be able to testify explaining his version of what happened.
Martin's mother Sybrina Fulton, who plans to attend every day of the trial, knows that the 911 call along with much the testimony may be difficult to bear.
"I pray for me to forgive," she said in an interview. "I don't want to block my blessing…The verdict in the trial will give us some type of closure, so we are looking forward to the trial."
Copyright 2013 ABC News Radio