George Zimmerman Trial: Ruling on Audio Experts’ Testimonies


george zimmerman trialOn June 25th, the George Zimmerman murder trial began, with both the prosecution and the defense making their opening statements. Therefore setting the stage for the rest of the trial.[1] During the previous weekend, however, Judge Debra Nelson ruled that the testimonies by the prosecution’s experts were inadmissible.[2]

As we covered last week (Technology Expert Witnesses in the Trayvon Martin Case), the court discussed whether to admit testimony from two experts, Dr. Alan Reich and Mr. Thomas Owen. At that time, their testimony was responsible for positively identifying the individual screaming on a 911 call as Trayvon Martin. In response, the defense called of their own four experts. They discussed the difficulty of obtaining a positive identification based on the audio that was available to them. It should be noted, however, that while the question revolved around the testimony of the experts, the 911 call, itself, was admissible (and was played for the jury on the first day of the trial).

Citing the Frye test, and its realization in Ramirez v. State, [651 So. 2d 1164 (Fla. 1995)], Judge Nelson ruled that the essential component of the test found in Ramirez, pertaining to the Zimmerman case, was whether the prosecution expert’s methodologies were based on a scientific principle or discovery. In particular, they must be, “sufficiently established to have gained general acceptance in the particular field it belongs.”[3] This is not strictly a measurement of what a majority of relevant practitioners believe, but rather the court should, “peruse disparate sources… and decide for itself whether the theory in issue had been ‘sufficiently test and accepted by the relevant scientific community.”[4]

With audio identification, there are three methodologies that are utilized by audio forensic engineers: auditory phonetic analysis, spectral or acoustic-phonetic analysis, and biometric analysis. The court must review the different methods, conclusions, and testimonies of the experts. The conclusion they came to was that aural perception and spectral analysis had been sufficiently established, but biometric analysis was not “widely accepted at this time.”[5]

Determining whether the application of technologies by the prosecution’s experts was sufficiently established to have gained general acceptance in the scientific community, the court noted that if a principle is, “untested and lacks indicia of acceptability, it was more likely to be ruled inadmissible.”[6] Also, having a personal (monetary) stake in a methodology indicated that the court should be more cautious of any conclusions.

Overall, this was the real issue with the prosecution’s experts, “The State did not offer any disinterested or impartial witness to establish that the scientific principles utilized by Mr. Owen and Dr. Reich testified in support of their own technologies and techniques…Although aural perception and spectral analysis are not new or novel, their application by the State’s witnesses to the samples from the 911 call in this case is a scientific technique that is new and novel.”[7] Jude Nelson ruling that the Mr. Owen’s and Dr. Reich’s testimony was not admissible because of this. This includes Dr. Reich’s testimony on specific words that he was able to make out on the 911 call.

In a footnote, the court acknowledged their transition to the Daubert standard, which should go into effect by July 1st. Consequently shifting the standard that the court will use to evaluate expert witnesses.[8] Still, this is a significant blow for the prosecution. Allowing testimony from a scientific authority, even limited, would have lent credence to the idea that Zimmerman was not acting in self-defense. Further highlighting the fact that, on the opening day of the trial, the 911 call played a prominent role as it was played for the court .[9]

As with most cases, there are some illustrative points for future litigation. When presenting new technology or a new application of an existing technology, it is critical that their methodology can be fully explained. In the Zimmerman case, it was not necessarily that the prosecution’s experts were using a new technology. Rather, they were using a methodology that was acknowledged by the court in a new way. Coupled with the fact that both experts were “interested” in their methodologies, the judge disallowed their conclusions. As the trial progresses, the 911 call may feature as prominently as it was on the first day. As a result, the identity of the individual screaming on the call is likely to be revisited by the litigating parties.