There may indeed have been a shot fired from the legendary grassy knoll 38 years ago, and it could likely have been the bullet that killed President John F. Kennedy, according to a new acoustical study.
"[T]he gunshot-like sounds occur exactly synchronous with the time of the shooting," writes Donald Thomas, author of the report which was peer-reviewed and published in Science and Justice, a journal of Britain's Forensic Science Society.
Conspiracy theorists for years have questioned the findings of investigators who concluded that Kennedy was felled by shots from a lone gunman, Lee Harvey Oswald, firing from a perch above the president's motorcade. This study bolsters that scrutiny by pinpointing a gunshot-like sound from a grassy knoll to the right of the motorcade and timing it to when the president was killed.
The study analyzes recordings made on two police channels on the day of the assassination in 1963. One was recorded when a motorcycle policeman in the president's motorcade inadvertently left a microphone on his vehicle switched on. Analysis of this channel later revealed a gunshot-like sound coming from the region of the grassy knoll. The second channel recorded routine transmissions from the lead car in the motorcade that was driven directly in front of the president's limousine.
Thomas claims a previous analysis done in 1982 by the National Research Council failed to accurately synchronize the two recordings and therefore incorrectly dismissed a gunshot-like sound originating from the grassy knoll since it appeared to occur at least a minute after the president was shot. By his own calculations, Thomas found there is a 96 percent likelihood a fourth shot was fired from the grassy knoll.
Despite the new findings, Norman Ramsey, a Harvard University physicist and lead author of the 1982 analysis, says he's still confident about his team's conclusions.
"We are very confident about our findings," Ramsey said. "Our calculations showed the timing of the shot was late — it occurred after the president was shot."
But Thomas, who conducts his research on the assassination independently from his work as an entomologist with a Texas branch of the U.S. Department of Agriculture, claims Ramsey's team overlooked a key excerpt in the recordings.
On both channels a patrolman identified as Sgt. S.Q. Bellah is heard to say: "You want me to hold this traffic on Stemmons until we find out something, or let it go?"
Thomas believes Bellah's words occur in both recordings more than a minute after the shootings because of a phenomenon known as cross-talk. Cross-talk happens when a transmission, picked up by an open microphone, causes interference and is rebroadcast at the same time over more than one channel.
After aligning the timing of the two recordings according to Bellah's cross-talk and after accommodating what Thomas determined was a 5 percent slower recording rate in one of the tapes, Thomas finds the shot-like sound from the grassy knoll is heard exactly at the moment the final shot was fired and the president was killed.
Unreliable Sound Bite
Ramsey's mistake, Thomas claims, was in relying on another segment of cross-talk to calculate the timing of the sounds. Rather than basing their calculations on Bellah's words, the 1982 team focused on Dallas County Sheriff Bill Decker when he's heard to say, "… hold everything secure."