http://www.orlandosentinel.com/videogallery/69143866/News/Trayvon-Martin-Audio-expert-extracts-911-screams-compares-to-Zimmerman-call
By Jeff Weiner, Orlando Sentinel
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 teen was shot?
A leading 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 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.

