By W. Anthony Marsh
Presented at The Third Decade conference June 18-20, 1993

As much as we would like to have direct evidence of a head shot from
the grassy knoll, such evidence may be missing, inconclusive, or suspect.
However, there may be a body of circumstantial evidence which would
indicate that the fatal shot which struck President Kennedy's head at
Z-313 came from the grassy knoll. This paper will not present conclusive
proof of a head shot from the grassy knoll, but it will cite examples of
circumstantial evidence which strongly suggest that the head shot came
> from the grassy knoll. Some of the examples are well known, but need to be reexamined. 

The Zapruder film is the most well-known evidence of the head shot.
Various studies and interpretations of it have been made. Some studies,such as the one done by Itek, have analyzed the movement of PresidentKennedy's head around the time of the head shot. They note that PresidentKennedy's head moves forward significantly from Z-312 to Z-313 and cite that as proof of a shot hitting the head from behind. What they and everyone else has failed to do is analyze the movements of all the occupants of the rear compartment of the limousine, including the Connallys. That is what I have done. 

My analysis of the movements of the Kennedys and the Connallys is
not, unfortunately, based on the same reproductions of the Zapruder film as used in other studies, due to cost considerations. I made measurements in 1/60th of an inch increments on a photocopy set of prints from Zapruder frames 312 to 321, as reproduced by Robert Cutler in his dividend to The Grassy Knoll Gazette of X-79. Bob's reference line is drawn through the center of the window knob. I made all measurements starting at the front edge of his reference line. However, I noticed that the distance from thereference line to the rollbar is not constant. This means that we can not use unadjusted measurements from these prints to calculate precise positions, but can estimate relative movements. This may be due to a variety of factors, such as variations in printing and copying each frame,changes in perspective, mismeasurements, or blurring. Some Zapruder frames
are too blurred to allow accurate measurements. Each measurement of Nellie Connally's position is to the front edge of her hair. Each measurement of John Connally's position is to the front edge of his forehead. Each measurement of Jackie Kennedy's position is to the front edge of her pillbox hat. Each measurement of JFK's position is to the edge of his hair at the rear of his head. All measurements were lined up against the chrome strip in the background for better contrast. Be sure to remember that increasing measurements for the Connallys represent forward motion, while increasing measurements for the Kennedys represent rearward motion. Noticethe direction and amount of movement of each person listed in Figure 1. Between Z-312 and Z-313, all the occupants of the rear compartment of the limo moved forward by about the same amount. Unless all four were hit by
bullets (a practical impossibility), their forward movement must be caused by something else. The most likely cause is inertia due to the limousine having suddenly slowed down. Dr. Luis Alvarez noted in his study [1] that the average velocity of the limousine going down Elm Street sharply decreased just before the head shot. Some researchers have theorized that Secret Service agent Bill Greer jammed on the brakes or took his foot offthe accelerator. Whatever he did, the limousine very quickly changed from an average velocity of about 12 MPH to about 8 MPH just before the head shot. Obeying the law of inertia, passengers in the limo were thrust forward in relation to their previous positions in the limousine. Further evidence of this effect is the fact that the Connallys continued to move forward while President Kennedy was being thrust backwards. I have not done a similar analysis of previous Zapruder frames to pinpoint the start of the occupants' forward movement, so I would urge others to do so
themselves, in order to verify my results and observations. Figure 1. 

 

Z-frame rollbar Nellie Connally Jackie JFK
----------+----------+----------+----------+----------+----------+----------+
x/60" Z312 136 106 77 44 159
----------+----------+----------+----------+----------+----------+----------+
difference 9 forward 5 forward 10 forward 6 forward 7
----------+----------+----------+----------+----------+----------+----------+
Z313 145 111 87 38 152
----------+----------+----------+----------+----------+----------+----------+
difference 2 forward 2 forward 1 rearward 1 forward 1
----------+----------+----------+----------+----------+----------+----------+
Z314 147 113 88 39 151
----------+----------+----------+----------+----------+----------+----------+
difference 4 0 forward 4 forward 6 rearward 6
----------+----------+----------+----------+----------+----------+----------+
Z315 151 113 92 33 157
----------+----------+----------+----------+----------+----------+----------+
difference 3 forward 2 forward 1 rearward 1 rearward 9
----------+----------+----------+----------+----------+----------+----------+
Z316 148 115 93 34 166
----------+----------+----------+----------+----------+----------+----------+
difference 2 forward 2 forward 7 forward 4 rearward 11
----------+----------+----------+----------+----------+----------+----------+
Z317 150 117 100 30 177
----------+----------+----------+----------+----------+----------+----------+
difference 3 forward 5 forward 2 rearward 5
----------+----------+----------+----------+----------+----------+----------+
Z319 153 122 NA 28 182
----------+----------+----------+----------+----------+----------+----------+
difference 0 forward 4 forward 3 rearward 14
----------+----------+----------+----------+----------+----------+----------+
Z320 153 126 130 25 196
----------+----------+----------+----------+----------+----------+----------+
difference 4 rearward 1 forward 1
----------+----------+----------+----------+----------+----------+----------+

Z321 157 NA NA 26 195 

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Perhaps the most controversial evidence produced by the House Select Committee on Assassinations would be the acoustical studies. In my opinion, the conclusion that there was a conspiracy should not rest entirely on the acoustical studies. But the acoustical studies are useful for establishing the time between shots. All times are measured in seconds after the microphone became stuck open for several minutes. BBN found 4 shots on the tape, 3 of which came from the TSBD at 137.70, 139.27, and 145.61 respectively. The grassy knoll shot was found by Weiss and Aschkenasy to be recorded at 144.90. There was a fifth set of impulses which was rejected by HSCA as being a false alarm at 140.32. I have looked at the waveforms more closely to try to determine when the muzzle blast of each shot was recorded, to a greater degree of accuracy. My best estimate for each shot is 137.702, 139.268, 140.339, 144.895, and 145.608. You can get a general idea of the spacing between shots by subtracting one time > from another. But there is an additional variable which must be taken into account. BBN found that the recorder used that day was running about 5% slow, so all times must be multiplied by about 1.05 in order to restore the original spacing. A more accurate correction factor might be borrowed > from the work which W&A did on the grassy knoll shot. They found that a correction factor of 1.043 produced the best fit for echo delays compared to their predicted model. Another possible corroboration for the 1.043 correction factor is the 'bell' sound found by BBN at 152.5. Although Todd Vaughan believes that it is only electrical interference, if we can determine its true frequency, we can derive the most accurate correction factor. That holds true for many other sounds on the tape, such as car horns, tire squeals, police sirens, etc. BBN found that the 'bell' sound had a nominal pitch of 420 Hz. This is close to the note A, which is usually 440 Hz. If the sound is really a bell, it might have been tuned to A=440. We do not know for sure what type of bell it was. Most people have assumed that it is a carillon bell, but it could be a train bell, a ship's bell, or a victory bell on a college campus. There are a couple of other possible tunings which would produce a correction factor close to 1.043. If the bell had been tuned using a mean-tone temperament scale, it might have a real pitch of 438.075 Hz. Dividing that by 420 would give us a correction factor of 1.0430357. If the bell had been tuned to an old English standard of A=438.9, dividing that by 420 would give us a correction factor of 1.045. Applying the correction factor to the spacing between shots as found by BBN will give us the true spacing between muzzle blasts picked up by McLain's cycle. If we want to then translate those into Zapruder frames, we must multiply each interval by 18.3 frames. Figure 2 is a rough approximation of how many frames there were between all 5 muzzle blasts. 

Matching these times to the Zapruder film is more complicated and depends on making several real-world assumptions such as the speed of the bullets. We can be fairly confident in ruling out the first three shots as matching the head shot at Z-313, as such a match would place the first shot after Z-255, when we can clearly see in Altgens 1-6 that President Kennedy and Governor Connally have already been hit. The HSCA matched the last shot with Z-313, because their medical evidence indicated that the head shot came from behind. My alternative matchup tests the idea that the head shot came from the grassy knoll. 

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Figure 2.
origin tape time spacing *1.043 *18.3 Z-frame Z-frame
TSBD 137.702 162 176
> 1.566 1.633 29.89
TSBD 139.268 192 206
> 1.071 1.117 20.44
TSBD 140.339 212 226
> 4.556 4.752 86.96
Knoll 144.895 299 313
> 0.713 0.744 13.61
TSBD 145.608 313 327

The first problem we notice with the HSCA version is that the first shot is much too early. No other evidence supports a shot that early and clearly President Kennedy was not hit by a bullet close to that frame. The first shot was probably a miss. The HSCA places the hit to JFK's back at around Z190- 192. The problem with that is that we can see President Kennedy in the Zapruder film during the range Z-190 to Z-210. He does not yet appear to be reacting to being hit by a bullet. There is absolutely no indication that Governor Connally was struck by a bullet at about that time, nor at about Z- 210 to Z-212, if we accept the fifth shot which HSCA rejected. 

My matchup would indicate a hit to JFK's back somewhere in the range of Z-206 to Z-210, and a hit to Connally's back somewhere in the range of Z-226 to Z-230. I believe this is more consistent with previous studies of the Zapruder film and eyewitness testimony. If there is some way to prove exactly when either President Kennedy or Governor Connally received their back wounds, that would force us to choose between the HSCA version and mine, regardless of other evidence. 

Just as Altgens 1-6 helps us eliminate the first three shots as matches with Z-313, it may also help us eliminate the last shot from the TSBD as matching Z-313. Everyone is familiar with the fact that CE350 shows a crack on the windshield and that it is not seen in Altgens 1-6, but is seen in Altgens 1-7. There has been some doubt about which shot > from which direction caused that crack. I believe that I am the first person to notice something in CE350 which would resolve the doubt. If you look carefully at CE350, you will notice that the back of the rearview mirror is dented, but you can see that it was not dented in Altgens 1-6. This damage was caused by a bullet fragment which struck the windshield > from the inside and ricochetted into the rearview mirror. Many people believe this fragment came from the head shot, which would been fired from the TSBD. I tend to feel that all the damage to the limousine, consisting of the crack in the windshield, dented rearview mirror and dented chrome topping, was done by the same shot. If we can find evidence which pinpoints when that damage was done, we may be able to show that it came several frames after Z-313. Photographic enhancement of the Zapruder film, Muchmore film or the Bronson film might reveal that the windshield was not cracked by Z-314. If that turns out to be true, then the last shot from the TSBD must have missed JFK's head and hit the windshield. In turn, that would mean that the fatal head shot came from the grassy knoll. I seriously doubt that there is any photograph which would show exactly when the rearview mirror was dented, but perhaps some as-yet-undiscovered photograph would show when the chrome topping was dented. That dent could only have been caused by a shot from behind the limo. If it was undented at Z-314, that would prove that the head shot came from the grassy knoll. Another factor which might influence our choosing the HSCA version or mine would be the jiggle analysis of the Zapruder film. Even the HSCA admitted that the jiggle analysis matched better when the grassy knoll shot was lined up with Z-313. [2] Figure 3 compares the timing of the impulses to the Zapruder film. The HSCA rejected the shot which is indicated in brackets as being too fast for Oswald to have fired. The jiggle analysis measured the amount of panning error by Zapruder. To simply and clarify, I have put the groups into ascending order. The group with the largest amount of blur is marked 'A', the second largest 'B', etc. I have chosen the Hartmann figures to be representative, as his are usually midway between Alvarez or Scott's figures. Zapruder's camera ran at 18.3 frames per second on average. 

Figure 3. Two comparisons of jiggle analysis to acoustical data
Frames Group 
158-159 D 
191-197 B Note that the start of a jiggle group may not 
227 C coincide with the firing or impact of a bullet. 
290-291 E In most cases, it takes several frames before 
313-318 A1 Zapruder reacts to a stimulus. 
331-332 A2
HSCA Z-# hit? origin jiggle Marsh Z-# hit? origin jiggle
137.70 161 miss TSBD D 137.702 179 miss TSBD VI#1 

B
139.27 191 JFK/JBC TSBD B 139.268 209 JFK TSBD VI#1
[140.32] 140.339 230 Connally TSBD VI#10
C
144.90 297 miss knoll E 144.895 312.6 JFK knoll 
A1
145.61 312 JFK TSBD A1 145.608 328 Connally TSBD VI#1 
A2


The jiggle analysis can not be used as absolute proof of when a shot occurred, but it matches up better for the head shot from the grassy knoll. 

Could eyewitness testimony help resolve the question of which shot hit what? Secret Service agent Clint Hill testified (2H144) that the last shot he heard sounded as though it had hit some metal place. If he in fact had heard the last shot from the TSBD hit the chrome topping, that would not, in and of itself, prove that the TSBD shot missed JFK's head, as the dent could have been caused by a fragment from the head shot. But it would narrow the range during which the chrome topping was dented to between Z-313 to Z-331 and make it more likely that the chrome topping was dented at the same time that the windshield was cracked, rather than much earlier as some have speculated. 

On pages 126-129 of Six Seconds in Dallas, Josiah Thompson cites the statements of several witnesses who thought that a shot came from the grassy knoll. William Newman felt that he and his family were in the direct path of gunfire. Given their position, it seems more likely that the head shot came from behind the fence on the grassy knoll than from the TSBD. Emmett Hudson, who was standing on the steps leading up to the pergola, said that the shots sounded as if they came from behind him, above his head and to his left. That would place the origin near the fence. Zapruder felt that the head shot had come from behind him and whistled past his right ear. Between these two witnesses and behind them is the corner of the fence. W&A found a probable shockwave at 24 ms. before the muzzle blast of the grassy knoll shot. Assuming the weapon was aimed at the limousine, we can make a rough calculation of the velocity of the bullet and the resultant angle of the shockwave. Although the calculation for the decay of the shockwave is too difficult for me, a rough calculation yielded an exit velocity of the bullet at about 1564.5 fps. This would create a shockwave of at least 45 degrees on either side of the flightpath of the bullet. All three witnesses were within the cone of that shockwave and would have felt it very strongly. 

How can we know whether the weapon was aimed at the limousine? If it had been aimed in some opposite direction, the open microphone would have been outside the cone of the shockwave and thus the shockwave would not have been recorded. Another indication of where the weapon was aimed can be found in the statement that Sam Holland made to Josiah Thompson when he was shown a very clear copy of the Moorman 2 Polaroid. He felt that the viewpoint was looking right down the barrel of the gun. Given Mary Moorman's position, the gun would have been aimed at the limousine. In
Moorman 2 we can see the head of a man peering over the fence, about 9 feet from the corner. Interestingly, this is the same spot where W&A located the origin of the grassy knoll shot, unaware of the existence of Moorman 2. In Moorman 2 we do not see a side view of any weapon as we might expect if it was not aimed at the limo. Whoever this man was, he moved from that position very quickly after the head shot. There is no one there in later Zapruder frames or in the Stoughton photograph, taken shortly after the head shot. The Stoughton photograph has never been analyzed. The Warren Commission and the House Committee were unaware of its existence. I believe that no one had ever studied it before I found it at the JFK Library. 

Unfortunately, I do not have the resources to properly analyze it and obviously the government will not, as it might reveal the presence of a gunman on the grassy knoll. One independent researcher, Dale
Meyers, has done some computer analysis which suggests that there is a person behind the fence, several feet to the right of the corner. Many witnesses can be seen reacting to the shots in various films.
Some fell to the ground very quickly while others did not seem to realize the danger. We would expect those witnesses closest to the gun on the grassy knoll to react very quickly and dramatically to the shockwave whizzing past them from the grassy knoll. One of the best films to observe their reactions was taken by Marie Muchmore. In Muchmore frame 42 we can see Hudson and his two companions on the steps leading up to the pergola.They do not seem to be reacting to any gunshots. In frame 55 we can see that two of the men are reacting. It seems inconceivable that these men would not have reacted to the sound of a shockwave coming from so close behind them. If the grassy knoll shot was the miss before the head shot, we would expect to see these men react before the head shot. The fact that they did not react until after the head shot would seem to indicate that the head shot came from the grassy knoll. 

Based on the circumstantial evidence we have now, I believe it is more likely that the head shot came from the grassy knoll. Existing evidence can and should be examined further. More information can be gleaned from existing data by novel analyses. The release of withheld data could provide new clues and allow us to verify certain methods, such as the acoustical studies. I urge other researchers to look for new evidence and perform new analyses. 
------

1. W. Peter Trower, ed., "Discovering Alvarez", (Chicago: The University Press, 1987), pp. 210-224. Also HSCA Vol. I, pp. 428-442.
2. House Select Committee on Assassinations, Report, p.80, footnote 16

 

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