The question of whose screaming can be heard in the background of a neighbor's 911 call on the night George Zimmerman fatally shot 17 year-old Trayvon Martin is quickly becoming a key point of contention in the case.
On Monday, the defense called five of Zimmerman's friends to testify that it was Zimmerman's voice on the call. "Yes, definitely. It's Georgie," said Sandra Osterman, the wife of Zimmerman's best friend, who also testified Monday. Her husband, Mark Osterman, has written a book, titled Defending Our Friend; The Most Hated Man in America.
The defense also called detectives Christopher Serino and Doris Singleton, who handled the Zimmerman shooting investigation. Both testified that Tracy Martin, Trayvon's father, had told them that it was not Trayvon's voice on the 911 tape.
Serino described Tracy Martin's response: “He looked away and under his breath, as I interpreted it, said, ‘No.’”
“There is no doubt he was telling us that — that didn’t sound like his son to him,” Officer Doris Singleton told the court.
The defense then called Tracy Martin himself to the stand, who contradicted the testimony of the officers. "I didn’t tell him, ‘No, that wasn’t Trayvon,'" the father stated. “I never said that ‘No that wasn’t my son’s voice.’”
Describing his reaction to Serino's questioning about the tape, Martin said, “The chairs had wheels on them and I kind of pushed away from the table and just kind of shook my head and said, ‘I can’t tell.’"
Martin testified that he heard the tape again several weeks later in the office of the mayor of Sandford, Florida. He stated that he listened to the tape at least 20 times, after which point he became convinced that the screaming voice was his son's.
"I was listening to my son's last cry for help," Tracy Martin said. "I was listening to his life being taken."
Last week, Trayvon Martin's mother, Sybrina Fulton, and brother, Jahvaris Fulton, both testified that they believed it was Martin's screaming on the tape.
On cross examination, defense attorney Mark O'Mara noted that Jahvaris had previously stated to a reporter that he couldn't be certain whether the voice on the recording was his brother's. "I guess I didn't want to believe that it was him, that's why during that interview I said I wasn't sure," Fulton said. "Listening to it was clouded by shock and denial and sadness."
It's becoming increasingly apparent that there is no way for the jury to objectively determine the identity of the voice screaming for help on audio recording of the 911 call. An FBI voice analysis expert testified last week that the only uninterrupted portion of screaming on the recording lasts just 3 seconds. He stated that existing technology wasn't sufficient to scientifically identify the voice, but that a family member or someone who knew Martin personally might be able to.
Unfortunately, any such witness with a personal connection to either the victim or the defendant is likely to be subject to an inherent bias. Both Zimmerman's and Martin's moms claim to hear their sons' voices crying out for help in the 911 call ... and maybe they both do.
For this reason, it may be impossible for the jury to decide who was really screaming in Sandford on the fateful night of February 26, 2012.
If you want to try to decipher the call yourself, you can listen to the full recording here. Be warned, as the audio is disturbing.
Gabe Grand is an editorialist for PolicyMic who covers the George Zimmerman trial. For more live updates and opinions on the proceedings, follow Gabe on Twitter: