The Daily Caller

The Daily Caller

Fla. judge to decide on whether 911 scream analysis is admissible in Zimmerman trial

Photo of Chuck Ross
Chuck Ross
Reporter, Daily Caller News Foundation

Whether or not voice identification experts will be allowed to testify in the George Zimmerman trial will be determined in a Florida courtroom today.

Circuit Judge Debra Nelson will hear arguments for the admissibility of testimony from experts listed on Florida prosecutors’ list of potential witnesses.  These experts claim to be able to offer analysis of a scream heard in the background of a 911 phone call that also captured the sound of the gunshot that killed Trayvon Martin in February 2012.

In court, Zimmerman’s defense team will try to argue that the methods used by the state’s potential witnesses are not proven and reliable under Florida’s Frye standard for evidentiary admissibility.

Zimmerman attorney Mark O’Mara wrote to the court that under Frye, “the ‘community acceptance’ standard exists to act as a valve to safeguard against the presentation of evidence by scientific methods that are not provably sound.”

If identified, that scream is pivotal to the case, set to begin June 10.

But academics in the field of voice identification tell The Daily Caller that the science behind matching voices to screams is still unproven.

Sadaoki Furui of the Tokyo Institute of Technology — and winner of Japan’s Royal Order of the Purple Ribbon award for his work in the field voice identification technology — told The Daily Caller that “there is no scientific or engineering method to correctly match a voice to a known scream.”

The scream voice is susceptible to psychological conditions and background noise, he said, “and it is almost impossible to make a good statistical model to cover such variation in each person.”

John Hansen heads the Center for Robust Speech Systems at the University of Texas – Dallas.  He agreed with Furui’s assessment and added that for voice identification analysis to be accurate “there needs to be some evidence based research that explores the variability of speaker identity across a range of screams from the same subject.”

He added, “the technology which has evolved successfully for speaker ID / verification has not been evaluated for scream detection in a scientific manner.”

Zimmerman’s defense has maintained the same argument.

If Zimmerman was the screamer, his defense that he was being viciously attacked by Martin would be supported.

Zimmerman has maintained that when he shot Martin at nearly point-blank range in the chest, Martin was on top of him, hitting him in the face and bashing his head against the ground “MMA style.” Zimmerman told police that he was screaming for help during the attack but that nobody would come to his aid.

Martin screaming for help would suggest that Zimmerman shot the teen in cold blood after relentlessly pursuing the “suspicious”-looking teen, even after he was told to stand down by a non-emergency dispatcher.

The second-degree murder charges pending against Zimmerman require that he was of a “depraved mind regardless of human life” and will be easier to prove to the jury if he is seen as having shot a victim pleading for his life.