One of the key pieces of evidence in the Trayvon Martin shooting case in Sanford, Fla., is who is heard screaming and crying for help shortly before the 17-year-old is shot by George Zimmerman. The voice is heard on a recording of a 911 call, and witnesses also said they heard screaming.

Zimmerman told police it's him. Family members of Zimmerman have said it's him. Trayvon's mother says it's Trayvon. Some witnesses also say it's Trayvon.

The claim goes to the key issue in the case, the fact that Zimmerman claims he shot the unarmed Trayvon in self-defense because the boy punched him to the ground and smashed his head into a concrete sidewalk.

The Orlando Sentinel called in an expert. He says the voice is NOT George Zimmerman's:



Tom Owen, forensic consultant for Owen Forensic Services LLC and chair emeritus for the American Board of Recorded Evidence, used voice identification software to rule out Zimmerman. Another expert contacted by the Sentinel, utilizing different techniques, came to the same conclusion. [...] Owen, a court-qualified expert witness and former chief engineer for the New York Public Library's Rodgers and Hammerstein Archives of Recorded Sound, is an authority on biometric voice analysis — a computerized process comparing attributes of voices to determine whether they match. [...] "I took all of the screams and put those together, and cut out everything else," Owen says. The software compared that audio to Zimmerman's voice. It returned a 48 percent match. Owen said to reach a positive match with audio of this quality, he'd expect higher than 90 percent. "As a result of that, you can say with reasonable scientific certainty that it's not Zimmerman," Owen says, stressing that he cannot confirm the voice as Trayvon's, because he didn't have a sample of the teen's voice to compare.

The pile of evidence bringing Zimmerman's claims into question grows deeper every day.

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See my diary: Protesters demand justice in Trayvon Martin case. An icon spreads.

