George Zimmerman will be back in court Friday for one final hearing before his second-degree murder trial for the shooting death of Trayvon Martin begins Monday.

Judge Debra Nelson spent much of Thursday hearing testimony from a voice expert who analyzed 911 calls made by witnesses of the shooting, in which someone -- either Zimmerman or Trayvon Martin -- can be heard screaming for help in the background. The defense wants to be sure the expert's methods are generally accepted by others in the same field.

The judge also suspended a lengthy hearing for sanctions against the state for allegedly withholding evidence from Trayvon Martin's cell phone, saying that can wait until after the trial.

Early in Thursday's hearing, the judge denied a defense request to let certain witnesses testify confidentially behind a screen.


Latest updates from the hearing

  • 4:45 p.m. - Nakasone says computer-aided methods of matching audio to a speaker is "at least" a few years away, adding all of his experience in this field says "it's not possible." He calls it "disturbing" that other scientists claim they can positively ID the screaming voice on the 911 call.
    Court in recess for the day. The hearing will continue Friday morning at 9 a.m. Join our LIVE Online Chat at 8:30 a.m. to follow along.
  • 4:30 p.m. - Nakasone said the screams heard on the 911 audio were by "someone who was facing probably imminent death," and were difficult to analyze, because there were only second seconds of unobscured screaming, and the screams could not be compared to "normal speech." He added he doubts any technology could match the screams to normal speech.
  • 4:15 p.m. - Don West plays the 911 call in court. Nakasone says his group tried to enhance the audio to "make everything audible," and they analyzed both the original version and the enhanced version. "I went through every segment of that utterance very carefully," he said.
  • 4 p.m. - Nakasone explains the difference between voice recognition technologies. Speaker comparisons are possible, but good audio is required. The technology returns a probability of a match, rather than a confirmation.
  • 3:45 p.m. - Nakasone says the FBI does not let its experts rely on spectrographic analysis in court, saying that technique "ran out of time to prove its utility."
    In explaining his statement that no one can speak in the same way twice, he says voices can vary based on emotional status. Distance is also a factor, and can add distortion or interference.
  • 3:30 p.m. - One state expert had concluded the voice screaming for help was Trayvon martin. Nakasone is testifying that the audio is too poor to tell, adding "Nobody can speak the same way twice."
  • 3:15 p.m. - After establishing himself as an expert in voice recognition, Nakasone said he previously concluded the quality of the provided 911 audio was too poor to determine who was saying what in an April 2012 analysis of the call.
  • 3 p.m. - Court resumes to take up the Frye hearing regarding the state's voice recognition experts. Dr. Hirotaka Nakasone, an expert from the FBI, is sworn in to testify.
  • 2:30 p.m. - SANCTION HEARING POSTPONED. Judge Debra Nelson stops the hearing on the motion for sanctions, saying it will have to wait until after the trial. The judge wants to move on to other motions that need to be address. Court is in a brief recess.
  • 2:20 p.m. - West outright accuses de la Rionda of withholding evidence in a heated exchange. There is visible tension between the two over this issue.
    The defense says Trayvon Martin's father originally did say it was not his son yelling for help, but later changed his mind.
  • 2:10 p.m. - West says the defense received a report from the state just two days ago. When asked by de la Rionda why the defense waited to release evidence to the state, West said they were busy trying to track down evidence they felt the state was withholding from them.
  • 1:50 p.m. - Defense attorney Don West says the discovered text messages from Trayvon Martin's phone involved talk about getting a .22 revolver and a 380. West also says he did not get the source file from prosecutors with thousands of pictures and deleted texts.
    "It's hard to say how much time that would have saved us," West says.
  • 1:40 p.m. - Court returns from recess. Defense attorney Mark O'Mara is questioning his partner, Don West, about evidence from Trayvon Martin's cell phone.
  • 12:40 p.m. - O'Mara asks Kruidbos if he thinks he is being pigeonholed. Kruidbos says he would prefer not to make those accusations, adding he does not have any anger toward de la Rionda.
    Kruidbos syas he created a screenshot comparing the two reports, one with "missing" pictures. He says he has not been told to put "specifics" in an email.
    Kruidbos is excused from the bench. Court is in recess for lunch until 1:40 p.m.
  • 12:30 p.m. - De la Rionda wraps up questioning of Kruidbos. Mark O'Mara begins to redirect.

  • 12:20 p.m. - De la Rionda asks Kruidbos is previous questioning about an incident in which he was accused of illegally leaking personnel information had anything to do with his coming forward about the unreleased evidence. Kruidbos says no.
    Kruidbos says he does not remember de la Rionda saying, "Let's get everything."
  • 12:10 p.m. - De la Rionda asks Kruidbos if his relationship with his current supervisor was troubled. Kruidbos said he has "had good conversations with her, and disagreements."
  • 12 Noon - Bernie de la Rionda is now asking Kruidbos how he arranged talks with Zimmerman's lawyers, pointing out that Kruidbos is not a forensic expert in this area.
  • 11:50 a.m. - Kruidbos says he was worried the additional pictures had not been turned over. He said because Bernie de la Rionda was close with Angela Corey, he did not fee comfortable questioning his handling of the evidence.
  • 11:40 a.m. - Kruidbos says he chose Wesley White to represent him because he is "a good lawyer," not because he's biased against the state. He says he wanted to make sure there was a fair trial. Kruidbos added he's worried he'll lose his job for blowing the whistle on prosecutors for not handing over all the evidence.
  • 11:30 a.m. - Kruidbos says he presented the deleted pictures to prosecutor Bernie de la Rionda. When he reported the uncovered evidence, Kruidbos' director supervisor said, "Good find."
  • 11:20 a.m. - Kruidbos says the FDLE found 2,958 photos, mostly small thumbnail images, but his report found more than 4,200. The photos he found included images of Trayvon Martin blowing smoke, along with pics of marijuana plants, jewelry, a gun, and nude "underage" girls. He says the photo of the gun was apparently taken with a cell phone camera, suggesting the person holding the gun took the photo.
  • 11:10 a.m. - Kruidbos tells Mark O'Mara the source file he obtained was much bigger in file size than the FDLE report, suggesting that report was not complete. He says he came across the evidence in January 2013. Zimmerman's attorneys said they did not get those photos from Trayvon Martin's phone until much later.
  • 11 a.m. - Ben Kruidbos, IT director for state attorney Angela Corey's office, is sworn in for testimony. He says he did not believe the FDLE report was conclusive, and asked for a source file. He explains it's not uncommon for a cell phone to miss a day or two of GPS information, and the FDLE report had not included any deleted information.
  • 10:52 a.m. - Judge Nelson has returned from recess. IT director-turned-whistleblower Ben Kruidbos is scheduled to testify.
    Martin family attorney Ben Crump releases a statement on the use of expert voice analysis testimony in trial:
    "It is ridiculous for the Zimmerman defense team to argue that expert voice analysts should not be permitted to testify at the trial when George Zimmerman himself stated the voice crying for help on the 911 recording 'doesn't even sound like me.' Zimmerman made this statement in his interview with Detective Chris Serino on Feb. 02/29/12 just 3 days after the tragic killing of Trayvon Martin. Expert voice analysis is necessary to assist in identifying the voices on the 911 tape."
  • 10:40 a.m. - The next scheduled witness is White's client, IT director Ben Kruidbos. Court is in a 10-minute recess.
  • 10:30 a.m. - White says he would never make up any information presented to court. He restates he is here because of the oath he took when he joined the Florida Bar in 1979. White's testimony is finished.
  • 10:20 a.m. - Defense attorney Mark O'Mara begins questioning White, who says bias is not a factor in his claim that the state withheld evidence.
  • 10:10 a.m. - Wesley White says he has not ruled out running against his former boss, Angela Corey, in the next election for state attorney, saying he hasn't made up his mind. White says he came forward on this issue out of his "obligation as an officer of the court," and had nothing to do with an alleged bias against Corey.
    White says he was happy with his time in Corey's office, calling it a wonderful opportunity to work there. He adds, "You know what 'assume' stands for, don't you? 'Make an a** out of "u" and me'?"
  • 10 a.m. - White clarifies that the pictures he claims the state did not turn over to the defense in a timely manner included photos of a gun, drugs and Trayvon Martin with an underage female. He also said there were texts regarding the "purchase and sale of a firearm." De la Rionda asks White if he asked why the IT director came forward. White says no.
    During White's testimony, Martin family attorney Natalie Jackson arrived in the courtroom.
  • 9:50 a.m. - Wesley White says he is representing an IT director who notified him about the pictures that White says the state withheld from Zimmerman's defense.
  • 9:40 a.m. - The state argues Wesley White may be biased against the prosecution from his time working for the state. Prosecutor Bernie de la Rionda asks White if he wanted to handle the Trayvon Martin case publicly. White's answer: He wanted every case.
  • 9:30 a.m. - MOTION DENIED: Witnesses may not be anonymous during trial.
    Next motion: Defense's request for sanctions against the state. Wesley White, a former prosecutor who worked under state attorney Angela Corey, takes the stand to testify. White resigned from Corey's office last year. At an earlier hearing, White testified that he contacted the defense to tell them that the state had not turned over photos from Trayvon Martin's cell phone, including pictures of a gun, Trayvon with an underage female, and what White identified as "drugs."
  • 9:20 a.m. - Media attorney Scott Ponce argues against anonymous witnesses, saying there has not been an evidentiary hearing to show why a witness should be anonymous, and the defense has not provided any basis for using a screen to hide witnesses. Prosecutors also say a screen for some witnesses could be "alarming or confusing" to the jury.
  • 9:10 a.m. - First issue: Defense's request for anonymous witnesses. Mark O'Mara says there are a "very few number of witnesses" who need to stay anonymous during the trial. He recommends a physical screen could be used to protect witness IDs. A media attorney, Craig Fugate, argues courts are public, including witness IDs "unless there are very compelling reasons."
  • 9 a.m. - George Zimmerman is in court for what may be the final hearing before jury selection begins June 10. State attorney Angela Corey is in the front row for the hearing.