General Discussion
In reply to the discussion: Attorney General Robert F. Kennedy believed President Kennedy was killed by a conspiracy. [View all]zappaman
(20,606 posts)'The Committee stated that there WAS, indeed, a 4th shot, as shown by accoustical evidence analysis put forth by the National Academy of Sciences. "
http://en.wikipedia.org/wiki/Dictabelt_evidence_relating_to_the_assassination_of_John_F._Kennedy
"The only evidence that HSCA had for a second shooter was the Dictabelt sound recording.[15][16][17] Four of the twelve HSCA members dissented to the HSCA's conclusion of conspiracy based on the acoustic findings, and a fifth thought a further study of the acoustic evidence was "necessary".[18]"
"In 2003, an independent researcher named Michael O'Dell reported that both the National Academy and Dr. Thomas had used incorrect timelines because they assumed the Dictabelt ran continuously. When corrected, these showed the impulses happened too late to be the real shots even with Thomas's alternative synchronization. In addition, he showed that, due to a mathematical misunderstanding and the presence of a known impulse pattern in the background noise, there never was a 95% or higher probability of a shot from the grassy knoll.[33]"
"In 2003, ABC News aired the results of its investigation on a program called Peter Jennings Reporting: The Kennedy Assassination: Beyond Conspiracy. Based on computer diagrams and recreations done by Dale K. Myers, it concluded that the sound recordings on the Dictabelt could not have come from Dealey Plaza, and that Dallas Police Officer H.B. McLain was correct in his assertions that he had not yet entered Dealey Plaza at the time of the assassination."
More here if you really want to learn...
http://mcadams.posc.mu.edu/odell/