Zimmerman’s Best Friends Testify It's Him Screaming On The 911 Call

July 5, 2013: George Zimmerman stands next to one of his defense attorneys, Don West, during his trial in Seminole circuit court in Sanford, Fla. (AP/Pool Orlando Sentinel)

"Yes, definitely. It's Georgie," said Sondra Osterman, after defense attorney Mark O'Mara played the 911 call that captured the confrontation between George Zimmerman and Trayvon Martin shortly before the former fatally shot the teen.

Osterman is one of three Zimmerman's friends and a former co-worker who took the witness stand Monday to testify that it's Zimmerman's voice screaming for help on a 911 call and not that of 17-year-old Martin.

Osterman testified she first met the accused in 2006 while working with him at a mortgage company and said that she and her husband, Mark, are the best friends of Zimmerman and his wife.

Zimmerman's mother and uncle testified last Friday it was Zimmerman screaming. Martin's mother and brother also took the witness stand last Friday to say the voice belongs to Martin. The 911 call is a crucial bit of evidence and has been played for jurors repeatedly because it could determine who the aggressor was in the confrontation last year.

Zimmerman, a former neighborhood watch volunteer who is half Peruvian, has pleaded not guilty to second-degree murder and says he shot Martin in self-defense during a scuffle in the townhome complex where he lived. Martin was there visiting his father and his father's fiancee.

Prosecutors contend that Zimmerman was profiling Martin and perceived the teen as someone suspicious in the neighborhood, which had been the site of a series of break-ins.

Under cross-examination, prosecutor Bernie de la Rionda implied that Sondra Osterman and her husband, Mark, had a stake in the outcome of the trial because they had written a book about Zimmerman's case and were donating the proceeds to their friend.

Mark Osterman took the witness stand after his wife to testify about how Zimmerman had chosen and purchased his firearm. He testified that Zimmerman could shoot with both hands, and he also said he recommended keeping the gun loaded.

He said it was Zimmerman's voice screaming when the 911 call was played for him in the courtroom.

Former co-worker Geri Russo also testified it was Zimmerman yelling on the call.

The prosecutor also played for Sondra Osterman a nonemergency police call Zimmerman made to report Martin walking through his neighborhood. In the call, Zimmerman uses the words, "F------ punks. These a-------. They always get away." Sondra Osterman identified the voice as Zimmerman's.

When asked by O'Mara if she detected ill will, spite or hatred in his voice, she answered no.

Prosecutors must show that Zimmerman acted with ill will, spite or a depraved mind in order to get a second-degree murder conviction.

Based on reporting by The Associated Press.