April 2nd, 2012
05:27 PM ET

Analysts: Questions surround 911 call analysis in Trayvon Martin case

Two experts who analyzed a 911 call made during the confrontation that ended in Florida teenager Trayvon Martin's death said they believe the screams heard in the background are not those of shooter George Zimmerman.

Zimmerman, 28, has claimed self-defense in shooting Martin on February 26. He said the 17-year-old accosted him after he called police to report Martin as a suspicious person walking around his neighborhood.

But the analysis poses some questions, legal analysts say, including whether it would be ruled admissible in court if charges are filed and the case goes to trial.

Audio experts Tom Owen and Ed Primeau analyzed the recordings for the Orlando Sentinel, and both said they believed it was not Zimmerman screaming.

"There's a huge chance that this is not Zimmerman's voice," said Primeau, a longtime audio engineer who is listed as an expert in recorded evidence by the American College of Forensic Examiners International. "As a matter of fact, after 28 years of doing this, I would put my reputation on the line and say this is not George Zimmerman screaming."

But is the analysis definitive enough for use in court? David Faigman, a professor of law at the University of California-Hastings and an expert on the admissibility of scientific evidence, said courts and the overall scientific community have mixed opinions about the reliability of such "voiceprint" analysis.

And CNN and HLN legal analysts Beth Karas and Sunny Hostin raised questions about what the public should consider regarding the conclusions reached.

Hostin says there are several questions and variables that must be considered, including the fact that the tests did not analyze similar speech. That is, the analysis was based on screams heard from a distance in a 911 call, compared with a direct phone conversation Zimmerman had with a 911 operator.

"Ideally, you want (Zimmerman or Martin's) voice saying the same exact thing, screaming 'help,' in order to analyze it," she said.

Would these tests even be admissible in court and considered evidence?

"It really depends on the individual judge," Hostin said. "In Florida, they are going to conduct a Frye test, the legal test, which asks if the science is generally accepted in the community."

Karas questioned whether the test stood up to the voice comparison standards of the American Board of Recorded Evidence, of which Owen is chairman emeritus.

 The standards indicate that when analyzing speech, there should be a minimum of at least 10 words to be compared with each other in order to say you can have a "possible elimination" conclusion. But in this case, the cries for help don't have nearly that number of words.

Owen said the published American Board of Recorded Evidence standards only partially apply to the kind of test he conducted.

"These standards apply to the older aural-spectrographic analysis and software," Owen said. "This only partially applies to the biometric software."

Both Karas and Hostin urged caution when it came to coming to a sure conclusion on the findings made by Primeau and Owen.

"I do think we need to take a step back, as with most of the facts in this case, and look at it the way the court would," Hostin said. "And that is by asking if the circumstances of how, and if, the test was done, OK, and wait to determine whether it's reliable."

- CNN's Greg Botelho and Mike Pearson contributed to this report.

soundoff (560 Responses)
  1. ♔Mmmmm♕

    cnn im beginning your motives are less than pure...you're trying this case in public and only sowing seeds of doubt to the jury pool...the only people buying into your grassy knowle theories are the red nxx haters who would never apply such lax standards of disregard if it had involved their son...a life had been taken without consideration for accountability or responsibility to the victim or the law...the courts is the place where this case should be tried...an civil rights violation complaint should be filed against the police department and the attorney general office as to why due process of the law fail to apply equitablly...trully a lawless disregard of the victim, his family, and the citizens of this country...how many days will pass before this man zimmerman is arrested and charged???how many more days???

    April 2, 2012 at 8:05 pm | Report abuse |
    • Sonya

      AMEN!!! Out side of all the evidence Zimmerman was the self admitted agressor when he stated he was following Trevon even when the dispatcher told him to stand down. That's probable CAUSE!!

      April 2, 2012 at 8:16 pm | Report abuse |
    • jim in washington

      This is a balanced and well reasoned presentation, but even if CNN were doing what you accuse them of, no harm comes of trashing red nex.

      April 2, 2012 at 8:18 pm | Report abuse |
    • Bill

      You cry about justice and obeying the law, but then you want the law to be ignored so Zimmerman can be arrested.


      April 2, 2012 at 8:25 pm | Report abuse |
    • Bill

      Probable cause for what, exactly?

      Here let me educate you: Florida is a "stand your ground" state. Generally that means any time you feel PHYSICALLY threatened, you can open fire. in Florida it specifically states: unless you can PROVE it was NOT self-defense, it was. That means no law was violated. That means Zimmerman should NOT be arrested. It is up to the police to poke holes in his story.

      Unfortunately for you & Trayvon's family though, witnesses and physical evidence so far back only Zimmerman. If you want him arrested, you're going to have to do some witness tampering first.

      April 2, 2012 at 8:32 pm | Report abuse |
    • â™”Mmmmm♕

      @billdolt...you need to catchup and catchon...your "tampered witnesses" renditions would never make it to the stand...and the only people ignoring the law is zimmerman, state atty general, the police chief and polic department...and stand you ground law do not apply to this case or to perps like zimmerman...

      April 2, 2012 at 8:53 pm | Report abuse |
  2. ♔Mmmmm♕

    state atty gen wolfinger so rightly called, unable to hand over justice to the citizens of florida or the victim's family...get the mark of the beast off your hand and do your job...and stop pointing your crooked finger at the innocent...ole moondog!

    April 2, 2012 at 8:14 pm | Report abuse |
  3. quantumelf

    "Which asks if the science is generally accepted in the community...." – please change this to "Which asks if the science is generally accepted in the SCIENTIFIC community...." – BIG difference there.

    April 2, 2012 at 8:15 pm | Report abuse |
  4. Leif Truitt

    That kid was a gangster plain and simple act like a thug get treated like one

    April 2, 2012 at 8:22 pm | Report abuse |
    • rafee

      and zimmerman was a law abiding citizen?

      April 2, 2012 at 8:57 pm | Report abuse |
  5. Salgar23

    People. To many assumptions are being made. I haven't read anything anywhere that's says Zimmerman continued to follow him after the dispatcher told him to stop. Did he? Or this that an assumption?

    April 2, 2012 at 8:24 pm | Report abuse |
    • Bill

      He did. That is not in dispute. What is in dispute is what happened after that, between the time Zimmerman lost sight of Trayvon and Trayvon ending up dead.

      Zimmerman claims Trayvon physically assaulted him.
      Witnesses, so far, have only backed Zimmerman's story, or have not been able to add anything useful.
      Physical evidence as well backs Zimmerman's story.

      If the FBI determine Zimmerman made any racial comments however, as is suspected by many, his self-defense case is gone as that only helps him in Florida, not with federal hate crime charges.

      April 2, 2012 at 8:36 pm | Report abuse |
    • cmonmaan

      Zimmerman was still pursuing Martin when he ended the call. Thats why he said he'd tell RO's where he was when the call. Call ended at 7:15, arguing then shot heard by 911 callers at 7:16. 7:17 RO is on the scene, 911 callers report seeing flashlight near body at the same time.

      April 2, 2012 at 8:59 pm | Report abuse |
  6. 23 from texas

    first report to the police, GZ said that the over 6 foot, 205 pound man on top of him went for his gun. That is very good reason for him to start yelling help. GZ used adiquate force to defend himself from an agressive attacker.

    April 2, 2012 at 8:25 pm | Report abuse |
    • Bill

      Trayvon has put on some significant weight since his death.

      He used to be a "little 140 lb dude"

      April 2, 2012 at 8:37 pm | Report abuse |
  7. steve

    The family attorney says that if Trayvon had pulled the trigger, he would have been arrested. Really? Really? Are you sure? Do you have a crystal ball? So I can assume that the entire system is racist and there would be no investigation etc. because a black kid shot a white man. So if the good family attorney was a player in the scenario, and he was about to be arrested, would he want the system to do it's job, or just MAKE AN ARREST based on what's in the media and what the public wants? Let the system work. I'm so tired of the ignorance.

    April 2, 2012 at 8:27 pm | Report abuse |
  8. Rush

    Rush ............ to judgement! A black man was killed under a claim of self defense, but it was a black man ...... let's convict without evidence. NOW!

    April 2, 2012 at 8:28 pm | Report abuse |
  9. gerard

    Have these so called experts ever heard zimmerman scream before?what are they using to compare the screams to.also have these so called experts ever heard. Trayvon scream before? Give me a break

    April 2, 2012 at 8:31 pm | Report abuse |
  10. Andso

    What else could these "experts" say... We know that if they go one way they get praised and exhalted by the leaders of the frenzied mob; and if they go the other they get attacked and hit by prosecution-style agression and abuse by that mob, professional outrage leaders, numerous reporters, most pundits, most talk show hosts, and vicious smiley masked comedians. What other stand could they possibly take?

    April 2, 2012 at 8:32 pm | Report abuse |
  11. Mary Ann Nadler

    Can similar analysis be done on Treyvon's voice in conversation he had with girlfriend just before he was killed?

    April 2, 2012 at 8:32 pm | Report abuse |
    • 23 from texas

      no because that call wasnt recorded. duh

      April 2, 2012 at 9:04 pm | Report abuse |
  12. Ackster58

    So, by your own reporting, we can't say for certain who is screaming for help. And although you had an "expert:" on who said it wasn't Zimmerman, the above story says they can't tell either way (too many variables).

    Other points to consider: We still don't have the timeline locked down. What if, when Zimmerman was told to break off his "persuit" he did so, and that was when he turned and headed back to his vehicle. If that's the case, then he was following instructions.

    And if Trayvon did confront him, and assault him, after Zimmerman turned back, he became the aggressor. Why didn't he just continue back to the father's girlfriends home? I don't know who is guilty of anything, or if it was just a tragedy. But both parties could have prevented/avoided it. It is just a shame that Zimmerman wasn't carrying a stun gun/pepper spray or some other form of "non-lethal" protection.

    Unlike many in the media, and the loudest voices protesting/screaming in the street, I honestly do want justice. True justice, which means we gather ALL the facts, and act accordingly. There are too many in the "civil rights" crowd who apparently don't care about the truth. They have made up their minds.

    April 2, 2012 at 8:34 pm | Report abuse |

    The security of our nation depends on electing as few repuglicans as possible......

    April 2, 2012 at 8:34 pm | Report abuse |
  14. SAVIOR at WGFN (who gives a fork news)

    I for one am sick of the news media and people like Nancy grace profiting on high profile cases. They tend to convict the accused or discredit the victim without knowledge of all the facts.all possible murder cases should be left out of the pubic eye until and arrest is made and a jury is selected. Florida does need to take a good hard look at their hold your ground law tho.it has a wild west feel to it. In my day if you got in a fight you either won or you lost and that was the end of it with the stand your ground law you have the right to kill somebody just for being a better fighter then you.hmmm something wrong with that..

    April 2, 2012 at 8:38 pm | Report abuse |
  15. Reggie from LA

    Look. Get the experts and their box of analytical stuff and go to the scene. Get that witness lady's phone and crank it up. Get a stick with little nails in it. Don't be ridiculous about he size of the nails. Little ones. Now tell "Z", "Listen. We're gonna poke you with this here stick. We will poke you as many times as necessary to get you to replicate the cries for help that you (you coward who had a gun and was out there screaming, duh. How stupid we are to buy this cr*p) made that night that your murdered Trayvon". Make sure you bring the scientific community. Test the stick on them a couple of times. Remember. Do it multiple times to ensure George has a fightin' chance. When the the machine says "alrighty then" I guess it was him hollering...a hundred pounds heavier...with a gun...to weak to counter a 170 pounder with 2 hands placed upon Z's head, pounding away. I CAN'T BELIEVE WE ARE HAVING RACE FIGHTS OVER THIS STUPID (I want to say the word, but what comes after stupid and rhymes with the state prosecutor's lack of WIT?)

    April 2, 2012 at 8:38 pm | Report abuse |
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