Updated at 2 p.m. ET: The voice heard crying for help on a 911 call just before Trayvon Martin was shot to death was not that of George Zimmerman, according to two forensic voice identification experts, one of whom told MSNBC on Sunday that he believes the evidence is strong enough to use in court.
"The tests concluded that it's not the voice of Mr. Zimmerman," Tom Owen, of Owen Forensic Services LLC and chair emeritus for the American Board of Recorded Evidence, told MSNBC.
Asked if he thought such tests would be admissible in court, Owen said "yes" and noted he had recently used similar testing in testimony at a Connecticut murder case that involved 911 call.
The conclusions of Owen and another audio expert were first reported by the Orlando Sentinel on Saturday.
Zimmerman told police that he screamed for help during his confrontation with Martin, 17. He claims the shooting was self-defense.
The 911 call, reposted in this YouTube clip, came on the night of Feb. 26 from a woman who reported someone crying out for help in a gated community in Sanford, Fla.
In the recording of her phone call, panicked cries and a gunshot are heard.
The Sentinel said it had contacted the two audio experts.
Owen told the newspaper he used software called Easy Voice Biometrics to compare Zimmerman's voice to the 911 call screams.
"I've run it against 300 voices and it was better than 99 percent in all cases," he told MSNBC when asked about its accuracy.
Owen told the newspaper that the software compared the screams to Zimmerman's voice and returned a 48 percent match. He said he would expect a match of higher than 90 percent, considering the quality of the audio.
"As a result of that, you can say with reasonable scientific certainty that it's not Zimmerman," Owen told the Sentinel.
But he also said he could not confirm the voice as Trayvon's, because he didn't have a sample of the teen's voice.
The Sentinel said that Ed Primeau, a Michigan-based audio engineer and forensics expert, used audio enhancement and human analysis and came to the same conclusion.
The 911 call mentioned in this story can be heard approximately six minutes into this clip.
"I believe that's Trayvon Martin in the background, without a doubt," Primeau told the newspaper. "That's a young man screaming."
On Feb. 26, Zimmerman, a white Hispanic, had called 911 to report a "suspicious" person and followed Martin against the dispatcher's advice. Martin and Zimmerman grappled, and Martin was shot in the chest.
Zimmerman told police that he was walking back to his vehicle when Martin attacked him and slammed his head against the ground and that he shot in self defense. Police declined to arrest Zimmerman citing Florida's "Stand Your Ground" law, which gives wide latitude to use deadly force when a threat is perceived.
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