SOMERVILLE, Mass. (AP) – It is a tantalizing tape recording, full of static hiss, popping sounds, and eerie faraway voices. And for years, there has been debate over whether it proves there was a plot to kill President Kennedy.
Now, a new analysis of the tape recorded by a Dallas police officer on the day Kennedy was assassinated casts further doubt on the lingering conspiracy theories.
Although some previous studies have suggested that one of the sounds on the tape is a gunshot from the infamous “grassy knoll,” forensic acoustics expert Bob Berkovitz said it was extremely unlikely that the sound was gunfire.
“The theory that the noise represents a ‘grassy knoll’ gunshot is not supported by the computer-based analysis,” said Berkovitz, chairman of Sensimetrics Corp., which specializes in research on speech and hearing.
Berkovitz studied the tape for Court TV for its special – “The JFK Assassination: Investigation Reopened” – which was to air Wednesday.
For those who believe a conspiracy was at work on the day JFK was shot – Nov. 22, 1963 – the tape is considered a key piece of evidence.
It is believed to have been made by a Dallas motorcycle police officer who accidentally left his microphone on during the chaotic minutes surrounding the assassination. The transmissions from the microphone were then recorded at police headquarters.
Although Lee Harvey Oswald is thought to have fired three shots from the window of the Texas Book Depository, the question of whether a fourth shot was fired by somebody else from the grassy knoll has been the subject of heated debate.
The House Select Committee on Assassinations, after hearing reports from acoustics experts who said there was a high probability that the tape contained four gunshot sounds, found in 1979 that the assassination was probably the result of a conspiracy. The Warren Commission, appointed by President Johnson to investigate the JFK shooting, found in 1964 that Oswald acted alone.
But a special panel of the National Academy of Sciences, led by a physicist from Harvard who would later win the Nobel Prize, disputed the evidence of a fourth shot in 1982.
Other studies have taken one side or the other and Berkovitz’s study doesn’t seem likely to be the last word in the long-running debate.
G. Robert Blakey, former chief counsel of the House committee and now a law professor at Notre Dame, said he was curious about Berkovitz’s analysis, but he stood by the House investigation.
“Did Oswald have help? I think there’s a high probability that there was a shot from the grassy knoll,” he said.
Berkovitz, who has testified in court cases as a forensic acoustics expert, analyzed the key segment of the tape using software developed by his company to help researchers analyze speech and other sounds.
Berkovitz seized on a snippet of conversation that can be overheard on the recording right at the point where the supposed grassy knoll “shot” is heard. The words “hold everything secure” appear to come from a second radio channel being operated by police that day.
The problem for conspiracy theorists is that the time of the transmission of the words “hold everything secure” on the second radio channel was about a minute after the assassination, meaning that the sound identified as the shot actually came a minute after the shots, according to Berkovitz.
It’s not clear how the sounds from one police radio channel could have leaked into another channel, said Berkovitz, but one possibility is that the microphone simply picked up sound from the loudspeaker on another officer’s motorcycle.
Some have argued that the later conversation could have somehow been recorded on top of the earlier gunshot sound, but Berkovitz said he had found evidence within the recording that the supposed gunshot and the radio transmission were recorded at the same time.
He said he went back one minute in the tape to see if he could find the assassination shots there, but had no luck. It was “an unholy mess. … There was lots of noise and not much else,” he said.
Berkovitz, who worked on the project for nine months, also said he used a computer program to calculate whether sounds on the tape represented echoes of the grassy knoll shot bouncing around Dealey Plaza. He said his analysis found a very high probability that the sounds were not echoes, a finding diametrically opposed to the findings that had swayed the House committee.
Noting that previous studies were carried out more than two decades ago, Berkovitz said, “I think it may well be that having some better tools at my disposal caused me to have different results.”
Still, Berkovitz doesn’t see his research as the last word.
“Those are the results I got,” Berkovitz said. “People are going to come along and say, ‘You’re full of it.’ That’s fine. That’s how science progresses.”
AP-ES-11-19-03 1705EST
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