The Zapruder film has also proved useful to official investigators in determining the location from which the gunfire came in Dealey Plaza and the trajectory of the bullets. By combining information about the location and track of the wounds (as determined by the autopsy of the president and the postoperative reports on the governor) with the relative positions of Kennedy and Connally as seen in the Zapruder film, both the Warren Commission and the HSCA sought to establish the location of the assassin, though the Warren Commission’s tests were more about proving Oswald’s involvement and validating the single-bullet theory than determining the source of the gunfire.
Since the Warren Commission had already found that the “cumulative evidence of eyewitnesses, firearms and ballistic experts and medical authorities demonstrated that the shots were fired from above and behind President Kennedy and Governor Connally, more particularly, from the sixth floor of the Texas School Book Depository,” the Commission’s trajectory analysis was only designed to ensure that all data was “consistent” with this premise.207 At the Commission’s request, the FBI and the Secret Service conducted an elaborate reenactment of the assassination in Dealey Plaza on May 24, 1964, using the 1958 Secret Service Cadillac follow-up car (which is similar in design to the actual 1961 Lincoln presidential limousine, which was being remodeled),*stand-ins for the president and governor (played by FBI agents with approximately the same physical characteristics), and Oswald’s Mannlicher-Carcano rifle. The rifle was outfitted with a camera (to photograph the view the assassin had through the telescopic sight) and mounted on a tripod in the sixth-floor window of the Book Depository Building. The locations of the president’s and governor’s back wounds (as determined by the medical evidence) were circled in chalk on the back suit coats of the stand-ins. The agents ascertained that the foliage of the oak tree between a gunman in the sniper’s nest and his target was “practically the same” on May 24, 1964, as it was when photographs were taken on December 5, just two weeks after the assassination.
Using frames from the Zapruder film (as well as the Nix and Muchmore films), investigators attempted to match, as closely as possible, the positions of their mock car and stand-ins with the positions of the president’s limousine and occupants as seen at various points in the films. As these alignments were completed, a straight line from the telescopic sight at the window through the chalk-marked wounds of Kennedy and Connally became very evident when the car was at the location recorded in Zapruder frames 210–225. A surveyor’s sighting equipment then measured the angle of declination from the rifle in the window to the entrance point on the back of the president’s stand-in to be 21.34 degrees at Zapruder frame 210 and 20.11 degrees at Z225, giving an average angle of 20.52 degrees. Allowing for the 3.9-degree downward slope of Elm Street, the Commission concluded that the probable downward angle of the bullet at impact was 17.43 degrees. (The angle of declination for the fatal shot to the president’s head was determined to be approximately 15.25 degrees.) The tests led the Warren Commission to conclude that the trajectory of the bullet that passed through the president and struck Governor Connally, and that of the bullet that hit the president in the head, were consistent with Oswald’s believed position in the southeasternmost window of the sixth floor of the Book Depository.208
Critics were quick to point out that the Commission’s approach assumed that the shots came only from the sixth floor of the Depository. Mark Lane wrote in Rush to Judgment that the Commission “employed the unproved assertion that the bullet which struck the President came from the rear as the basic premise to prove that it ‘probably’ hit Governor Connally as well.”209 Sylvia Meagher charged, in Accessories after the Fact, that the Commission did not give “adequate consideration to the possibility of assassins at locations other than the window or the overpass.”210 Josiah Thompson’s analysis in Six Seconds in Dallas concluded that four shots were fired from three different locations.211 “It would seem that the critics have at least one point in their favor in attacking the Commission’s analysis,” G. Robert Blakey, HSCA chief counsel, told the HSCA in 1978. “The analysis assumes the firing position of the assassin as a known, then proceeds to compute the angle to the target.”212 True, but if the trajectories failed to match up with the subject sixth-floor window, the assertion that the sixth-floor window was the source of the shots would automatically fall.
In any event, the HSCA took a different approach, one that made no assumptions as to the origin of the shots. It was an interdisciplinary effort, principally based on the expertise of the forensic pathologists, photographic analysts, and an engineer from the National Aeronautics and Space Administration (NASA), Thomas Canning, who plotted the trajectories by starting with the location of the wounds and working backward to the source.213 “To the best of my ability,” Canning told the HSCA, “I put myself in the position of assuming that no gun was found and simply say, Where would I look?”214 Like the Warren Commission, Canning’s trajectory analysis relied heavily, of course, on the Zapruder film and Zapruder’s line of sight (his location was determined from photographs taken of him by photographers on the south side of Elm Street) to pinpoint the location of the car and the positions and relative alignment of the president and the governor within it. However, unlike the Commission, Canning’s analysis did not require an on-site reenactment. The location of the president’s limousine was instead determined through analytical photogrammetry conducted by the U.S. Geological Survey in Reston, Virginia. Using enlargements of six frames from the Zapruder film, the U.S. Geological Survey group plotted the position of the limousine, at various intervals throughout the assassination, on a survey map of Dealey Plaza.215 Armed with the position of the limousine, the position of its occupants (as deduced from the Zapruder film by the photographic panel), and the precise location of the wounds in President Kennedy’s and Governor Connally’s bodies (as provided by the HSCA’s forensic pathology panel), Canning proceeded to calculate three separate trajectories to ascertain the source of the bullets—one for the bullet that caused the president’s upper back and neck wounds, one to test the hypothesis that the bullet that exited the president’s neck also went on to cause the wounds to Governor Connally, and a third trajectory for the bullet that caused the president’s head wound.216
Canning concluded that the bullet that struck Kennedy in the upper back was descending at an angle of 21 degrees below horizontal as it approached him (recall the Warren Commission concluded 17.43 degrees) and was 26 degrees to the right of true north from the president. (The Warren Commission made no such computation, though its trajectory analysis showed that the source of the bullet was to the president’s right rear at the sniper’s nest.) He concluded the bullet that struck Kennedy in the head was descending at an angle of 16 degrees below horizontal (recall the Warren Commission concluded 15.25 degrees) and came from a point 29 degrees to the right of true north from the president.217 (Again, the Warren Commission made no such computation.)
With respect to the first trajectory, Canning used the locations of the entrance and exit wounds to the president’s upper back and neck, and the position of the limousine at Zapruder frame 190. (Canning was instructed by the HSCA to calculate a trajectory based on Z190 because of the committee’s conclusion of a shot at Z188–191.) Canning connected the entrance and exit wounds with a straight line and projected that line backward to determine the source of the shot. He found that the line representing the trajectory of the shot through Kennedy’s upper back and neck originated from a point just west of the first window at the southeast corner of the sixth floor of the Texas School Book Depository Building, where all the physical evidence shows Oswald was at the time of the shooting in Dealey Plaza. Canning then went through each stage of his analysis and made a point-by-point estimate of how accurate each step was and by how much an error might shift the calculated source of the gunfire. Adding the possible errors together generated a circle around the subject window with a radius of thirteen feet, which simply meant that the
shot that hit the president, even when all errors in calculation are taken into account, was fired from somewhere within that area or cone. Oswald’s sixth-floor sniper’s perch was within the region described by Canning’s analysis.218
To determine the validity of the theory that the bullet that pierced the president’s upper back and neck (already shown by Canning to have originated from the sixth-floor sniper’s nest) went on to strike Governor Connally, Canning next used the exit wound on the front of the president’s neck and the entrance wound in the governor’s back to calculate a second trajectory. (The governor’s other wounds were not used because of the photographic panel’s belief that the missile had been “significantly deflected” during its course through his body when it struck “at least two bones at oblique angles.”)219 Canning concluded that the bullet that struck Connally’s back was proceeding on a downward trajectory of 25 degrees below horizontal.220
Projecting this trajectory backward* from the position of the two wounds and the limousine’s location at Z190, Canning found that it again terminated on the front face of the Depository, this time at a point approximately two feet west of the southeast corner of the building and about nine feet above the sill of the sixth-floor corner window. A similar set of calculations for the cumulative margin of error produced a circle with a seven-foot radius.221 This not only clearly identifies the sixth-floor sniper’s nest as the source of the second shot, but is strong evidence in support of the validity of the single-bullet theory. In fact, Canning told the HSCA, “The bullet would have had to have been substantially deflected by passing through the president in order to miss the governor. It seems almost inevitable that the governor would be hit with the alignments we have found.”222
Finally, Canning and his team felt that the trajectory of the shot to the president’s head would be the easiest to calculate, partly because they knew the time and location of the injury so precisely, and partly because the head is a rigid object and less subject to the vagaries of posture and bodily movement. The key evidence for the third shot was, of course, Zapruder frame 312 (one-eighteenth of a second before the explosion to the president’s head at Z313), supported by corresponding frames from the films by Orville Nix and Marie Muchmore. To project this third trajectory path, Canning relied on two sketches (frontal and right lateral view) of the entrance and exit wounds crafted by the HSCA’s forensic pathology panel from measurements they made of the autopsy photographs and X-rays.† The orientation of the president’s head in relation to Zapruder’s camera was determined by comparing Zapruder frame 312 with a series of calibration photographs (photographs of a likeness or replica) of Kennedy’s head prepared by the Physical Anthropology Section of the Federal Aviation Administration. The calibration photograph that best matched the features seen in Z312 (such as the back of the head, the position of the right ear, the projection of the nose beyond the rest of the facial profile, and the shape of the brow) was used to obtain the relative positions of the head wounds to Zapruder’s camera.223 A straight line was then drawn between the exit and entrance wounds and extended rearward from Kennedy’s position in the limousine at Z312. Canning found that line tracked back to a point approximately eleven feet west of the southeast corner of the Texas School Book Depository Building and fifteen feet above the sixth-floor windowsill.224 An estimate of the margin of error in the calculations, like before, produced a circle with a twenty-three-foot radius, a cone area much larger than what previous error calculations showed, owing to the fact that the limousine was now more than a hundred feet farther down Elm Street. This larger error circle included the top four floors and the roof of the southeastern end of the building, extending slightly beyond the southeastern corner. But the only open, unaccounted-for window (the three open windows on the fifth floor were occupied by the three black Depository employees) within the margin of error was the sixth-floor sniper’s nest window.225
The HSCA concluded that “all three trajectories intercepted the southeast face of the Texas School Book Depository Building. While the trajectories could not be plotted with sufficient precision to determine the exact point from which the shots were fired…the margins of error were indicated as circles within which the shots originated. [And] the southeast corner window of the [sixth floor] of the Depository [where police found the three spent cartridges and where eyewitnesses saw a rifle being fired] was inside each of the circles.”226 (See the three trajectories back to the southeasternmost area of the Book Depository Building, with ovals representing margins of error, in the photo section. This photo of the front of the Book Depository Building was taken by Dallas Morning News photographer Tom Dillard just moments after the third shot was fired.)227
Although Canning’s trajectory analysis may not have been perfect, he had successfully determined the source of gunfire: the vicinity of the sniper’s nest in the Book Depository Building.
Fifteen years later, in what can only be characterized as a terrible, terrible slap in the face to the personnel of the HSCA and Warren Commission, whose painstaking efforts had established scientific proof that the alignment of Kennedy and Connally in the presidential limousine assures us of the validity of the single-bullet theory, and that all of the gunfire originated from the Texas School Book Depository, Case Closed author Gerald Posner claimed that the single-bullet theory was still an open question—one that he apparently was instrumental in finally solving. In his 1993 book, Posner wrote that “Failure Analysis Associates applied the latest computer and film enhancement technology to answer the question of whether one bullet could have caused the wounds [to Kennedy and Connally].”228 He quotes Dr. Robert Piziali, described as overseeing the Failure Analysis tests, as stating that in Failure Analysis’s reenactment of the assassination, “the most important factor was to have the President and the Governor in the exact locations [alignment] they were at [at] the time they were shot.” You mean we had to wait almost thirty years to find this out? Unbelievably, the Case Closed author could only find space in his book to say, and then in just one single sentence of his book, that “the Warren Commission and the House Select Committee did the best they could with photo and computer technology as it existed in 1964 and 1978” to solve the problem. He goes on to say, “However, scientific advances within the past five years allow significant enhancements of the Zapruder film, as well as scale re-creations using computer animation, which were unavailable to the government panels. As a result, it is now possible to settle the question of the timing of Oswald’s shots and to pinpoint the moment when both Kennedy and Connally were struck.”229*
There’s only one way, not two, to read what Posner wrote: that the Warren Commission and HSCA were both unsuccessful in solving these critical issues. (“They did the best they could” with the technology that was available to them in 1964 and 1978, the author allows generously.) Nowhere in his book does Posner tell his readers that the Warren Commission and HSCA reached the same result that Failure Analysis did many years later. Indeed, nowhere in his discussion of the alignment of Kennedy’s body to Connally’s and the issue of the single-bullet theory does the Case Closed author describe the elaborate 1964 on-site reconstruction of the assassination conducted by the Warren Commission to confirm the single-bullet theory.* And remarkably, NASA’s Thomas Canning and the comprehensive, sophisticated tests he conducted for the HSCA, which were far more sophisticated and in-depth than anything even attempted by Failure Analysis, involving frequent coordination with experts as diverse as the HSCA’s forensic pathology panel and the Federal Aviation Administration’s Civil Aeromedical Institute, are not even mentioned in Posner’s book. Not one word. Instead, as indicated, the Case Closed author presents the results of Failure Analysis’s work on the alignment and single-bullet theory issue as if it was a new revelation.230
As we’ve already shown, the Warren Report, way back in 1964, concluded that “the bullet that hit President Kennedy in the back and exited through his throat most likely could not have missed both the automobi
le and its occupants. Since it did not hit the automobile…it probably struck Governor Connally.”231 The Warren Commission, of course, was being far too circumspect in its conclusion. As FBI firearms expert Robert Frazier and wound ballistics expert Dr. Frederick W. Light Jr. testified, the bullet that passed through the president’s neck had to cause Connally’s wound, a fact demonstrated by Arlen Specter, a chief expositor of the single-bullet theory, in a 1964 photograph.232 And, as we have seen, the HSCA in 1978 went over the entire single-bullet theory in even more depth than the Warren Commission and reached the same conclusion. When HSCA counsel asked Thomas Canning whether a bullet fired from the southeasternmost window of the sixth floor of the Book Depository Building and passing through Kennedy would “of necessity” have gone on to hit Connally, he answered, “The bullet would have had to have been substantially deflected by passing through the president [and everyone agrees, even the conspiracy theorists, that it was not, passing through soft tissue on a straight line] in order to miss the governor. It seems almost inevitable that the governor would be hit with the alignments that we have found.”
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