By Barbara Liston
ORLANDO, Florida (Reuters) - Two voice identification experts who suggested that unarmed black teenager Trayvon Martin screamed for help before he was shot and killed by George Zimmerman will not be allowed to testify at his murder trial, the judge in the case has ruled.
The ruling by Judge Debra Nelson was released on Saturday, marking the last major hurdle before opening statements in the high-profile case begin on Monday in Seminole County courthouse in Sanford, Florida.
Prosecutors had sought to call audio experts to testify about a 911 emergency call in which screams for help can be heard in the background during an altercation between Zimmerman and Martin before the shooting.
The screams could be pivotal evidence and help identify who was the aggressor on the night of the February 2012 killing. Zimmerman's family and supporters claim the voice was his, while Martin's parents insist the voice belonged to their son.
Last year, an FBI expert said a voice analysis of the call was inconclusive.
David Weinstein, a Miami lawyer and former prosecutor, called the ruling a victory for Zimmerman's defense team.
"Now there won't be a witness who can 'identify' the voice with certainty as a particular person," he said. "Each side can argue who they believe the voice belongs to and the jurors will have to decide who they hear."
Prosecutors say Zimmerman followed and confronted Martin despite a police dispatcher telling him not to pursue the 17-year-old. Zimmerman, 29, has said the two fought and that he shot Martin because he feared for his life.
An all-female jury will decide whether Zimmerman is guilty of second-degree murder, a charge that carries a potential life sentence. Zimmerman has pleaded not guilty.
Nelson said in her 12-page order that the decision does not prevent either side from playing the 911 tape and presenting witnesses familiar with Zimmerman's and Martin's voices from stating their opinions.
Lead defense attorney Mark O'Mara has called the recording "the most significant piece of evidence in the case."
Two state experts, in what they qualify as tentative or probable findings because of the poor quality of the recording, have said that the chilling screams heard in the background came from Martin.
Lawyers for Zimmerman, a former neighborhood watch volunteer, sought to block the testimony on grounds that the methods used by the state's voice recognition experts were based on questionable science.
Audio experts who testified for the defense in a lengthy pre-trial hearing argued that voice recognition techniques cannot identify an individual from screams made under extreme duress.
On Friday, the judge also dismissed a defense motion to bar certain words and phrases from the prosecution's opening statement.
She ruled prosecutors could allege that Zimmerman, who is Hispanic, "profiled" Martin but ordered them not to use the term "racial profiling."
(Additional reporting by David Adams; Writing by Kevin Gray; Editing by Eric Beech and Eric Walsh)