In what may turn out to be a key evidentiary ruling in a trial that starts on Monday, the Judge in George Zimmeman’s murder trial is barring the prosecution from putting on expert testimony to attempt to establish the identity of the person heard screaming on a 911 recording on the night Trayvon Martin was shot dead:
In a major victory for murder suspect George Zimmerman, a judge today ruled that prosecutors may not put on the witness stand two state audio experts who say the voice heard screaming for help on a 911 call was someone other than Zimmerman.
Those screams, recorded while Zimmerman was fighting with 17-year-old Trayvon Martin, are the most dramatic piece of evidence in the high-profile murder case.
Zimmerman, a Neighborhood Watch volunteer, says they came from him, that he was calling for help after Trayvon attacked him. Trayvon’s parents say they are from their son and are his last words before Zimmerman shot him in the chest.
Circuit Judge Debra S. Nelson had heard three days of testimony about the science used by the state’s experts to analyze them. Today she ruled that it failed to meet Florida’s legal standard.
One of the experts, Alan R. Reich, had concluded the voice he identified asTrayvon is heard yelling, “I’m begging you,” and “stop.” The other, Tom Owen, ruled Zimmerman out as the screamer, in part, after using voice recognition software.
Both witnesses are now banned from Zimmerman’s trial, which began two weeks ago with jury selection. Opening statements are set for Monday morning.
The judge barred both experts, she wrote, because prosecutors failed to present competent evidence that the techniques used by Reich and Owen were generally accepted in the scientific field.
The state presented no evidence, except Reich and Owen themselves, who defended their findings, she wrote.
She gave special attention to Reich. None of the five other experts who testified heard the words and phrases that he did, she wrote.
His testimony, she wrote, “would confuse issues, mislead the jury and, therefore, should be excluded from trial.”
The recording is that of a neighbor, who had called 911 to report the fight. The screams and gunshot can be heard in the background.
Four defense experts had challenged Reich’s and Owen’s findings, testifying that using screams to identify someone’s voice is impossible. Valid voice comparisons can only be made if someone speaking in a normal voice, they said.
The judge noted that three of the defense experts, including FBI analyst Hirotaka Nakasone, said they were “disturbed” by the state experts’ conclusions.
Assistant State Attorney Richard Mantei urged the judge Thursday to admit the testimony anyway.
“The evidence should be heard by the jury, and let them decide,” he said.
While I didn’t follow the arguments on this motion closely, what I have read, including the Judge’s 12 page opinion below, indicates to me that the Judge got this ruling largely correct. The purpose of an Expert Witness is supposed to be to aid the trier of fact, whether that be the jury or the judge, in understanding some information that is outside the range of knowledge of the average person. Medical Doctors are frequently Expert Witnesses in personal injury cases, for example, because their specialized knowledge can help the jury understand the relationship between the injuries that the Plaintiff suffered and the facts already established about how the incident alleged to be responsible for those injuries. Medical and forensic experts also frequently testify in criminal trials regarding the evidence found at the scene of the crime, the cause of death, and the approximate time of death based on appropriate medical testing. Uses for experts go beyond the medical field, though, and are often used in cases involving construction, forensic accounting, or any other number of fields where some complex issue plays a key role in the case. Quite often, the opposing side has its own expert witness whose primary task is to attempt to rebut the conclusions being offered by the party who offered the expert testimony.
There are several limitations placed on expert testimony, though. In general, for example, expert witnesses will not be permitted to testify regarding an issue that is supposed to be a question that the trier of fact. For example, so-called “accident reconstruction” experts are generally prohibited from testimony that suggests one party or the other was responsible for a traffic accident, and in some states they are forbidden from testifying at all. Most importantly for this case, though, is the rule that states that any expert testimony with a scientific or technological basis must be ‘generally accepted” in the particular field in which the expert is presented as having expertise. In the case of this Zimmerman ruling, that field would generally be the field of analysis of audio recordings. Given the fact that both the expert presented by the prosecution, who identified that scream as most likely coming from Martin,and the defense expert who identified Zimmerman as the source of the scream, were properly barred from testifying. As noted in the article above and the opinion below, there were four independent experts each of whom stated that it was impossible to make a determination of who the scream came from with any degree of scientific certainty. The only thing that allowing either, or both, of these experts to testify would have accomplished is to confuse the jury needlessly.
This ruling doesn’t mean that the 911 recording cannot be introduced at trial for the purpose of each side presenting non-expert testimony regarding the identity of the screamer. Indeed, in her order the Judge explicitly states that the recordings can be introduced for that purpose. Most likely, we’ll have the prosecution put Martin’s mother on the stand to say that the screamer’s voice is the voice of her son, while the defense will put on Zimmerman relatives, and likely Zimmerman himself, to say that he is the person screaming. In the end, it will be up to the jury to decide what to believe about that, and they may well decide that both sides witnesses cancel each other out, which would essentially mean that they wouldn’t be giving that much weight to that particular piece of evidence. For that reason alone, I’d suggest that this ruling constitutes a victory for the defense because all they have to do is create some reasonable doubt regarding the prosecutions case to win.
Here’s the opinion:
Florida v. Zimmerman Order Excluding Expert Testimony by dmataconis
