Trayvon Martin's mom ID's screams

ORLANDO -- A key piece of evidence was at the center of George Zimmerman's murder trial Friday.

Trayvon Martin's mother and brother listened in court to a 911 call on the night of the shooting and said they recognized the screaming on the recording as coming from the slain teen.

Zimmerman is charged with second-degree murder. His defense team argues that he shot the teen in self-defense.

Lawyers on both sides want to convince the jury of who was doing the screaming, Zimmerman or Martin.

The audio was played in court for Martin's mother, Sybrina Fulton. She said she recognized the screaming as that of "Trayvon Benjamin Martin."

Defense attorney Mark O'Mara asked Fulton if she had no doubt that it was her son screaming.

"Absolutely," she said.

Martin's older brother, Jahvaris Fulton, 22, also took the stand Friday.

Prosecutor Bernie de la Rionda asked him if he recognized the voice on the tape.

"My brother's," Fulton said, adding that he had "heard him yell" before, but "not like that."

The question of whether Zimmerman's actions were self-defense or murder could rest on who was the person screaming.

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