As the Trayvon Martin controversy splinters into a debate about self-defense, a central question remains: Who was heard crying for help on a 911 call in the moments before the teenager was shot?

An expert in the field of forensic voice identification sought to answer that question by analyzing the recordings for the Orlando Sentinel.

His result: It was not George Zimmerman who called for help.

Tom Owen, forensic consultant for Owen Forensic Services and chairman emeritus of the American Board of Recorded Evidence, used voice-identification software to rule out Zimmerman, a neighborhood watch volunteer who shot Martin, an unarmed 17-year-old, on Feb. 26. Another expert contacted by the Sentinel, using different techniques, came to the same conclusion.

Zimmerman claims self-defense in the shooting and told police that he was the one screaming for help.

Owen used software called Easy Voice Biometrics to compare Zimmerman’s voice to the 911 call screams.

The software returned a 48 percent match. Owen said to reach a positive match with audio of this quality, he would expect higher than 90 percent.

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