Who screams on 911 call in Trayvon Martin case?

Screams recorded on a 911 call during the confrontation that ended in Florida teenager Trayvon Martin's death don't seem to be those of neighborhood watch volunteer George Zimmerman, two audio experts who analyzed the recordings said Monday.

Zimmerman, 28, has claimed self-defense in the February 26 shooting, saying Martin accosted him after he had called police to report the teenager as a suspicious person walking around his neighborhood.

But audio experts Tom Owen and Ed Primeau, who analyzed the recordings for the Orlando Sentinel using different techniques, said they don't believe it's Zimmerman who can be heard screaming in the background of the 911 calls.