Randy Robertson Replies to his Critics

[James DiEugenio]

This is over his review of Thompson's Last Second in Dallas.  This is all kind of odd to me since Randy ended up liking the book.  I mean we cannot all agree on every point but I thought Randy gave Tink's book an overall positive rating. Someone even placed parts of it on the book's page on Amazon.

https://kennedysandking.com/john-f-kennedy-reviews/a-final-response-to-the-rebuttal-of-my-review-of-the-book-last-second-in-dallas

 

 

[James DiEugenio]

BTW, Randy furnished a link to the actual attack on his review in the posted article above. 

In fact its in the first sentence.

[Anthony Mugan]

Thanks for posting such an interesting discussion on your site...

I’d be interested in if there is any sort of ‘majority view’ on several of the points discussed. For reasons if space, time and focus I’ll raise these questions one a time if that’s OK, with initially some discussion of the reasons for each question.

Dr Robertson makes a point that the pattern of fractures in JFK’s skull strongly supports the idea that he received a severe blow to the back of the head shortly before the fatal headshot at Z312/3 hit at the front right (if memory serves, which in may not, Cyril Wecht originated that idea). That point strikes me as very persuasive but as critics have pointed out the acoustic evidence precludes the idea that this impact occurred 0.1 seconds prior to the grassy knoll shot.

Logically the impact on the rear of the skull does not have to have occurred so close to the grassy knoll shot. The evidence presented for that timing is the forward movement of JFK in that time frame but others have pointed out that the car was decelerating at time, leading to a natural forward motion (see Thomas, 2014, ‘’Hear no Evil’ Chp 10 for a review and references).

There was a bullet fragment recovered pancaked onto the outer surface of the skull, under the skin just below the high positioned wound at the back of JFK’s skull. As others have pointed out that suggests a fragment from a ricochet from one of the earlier shots hit JFK causing the initial fracture pattern. This might be consistent with Kellerman’s recollection that Kennedy exclaimed he had been hit, which would be unlikely to have occurred after the shot through the throat.

So...would people agree that both papers make valuable points in this regard and that evidence suggests JFK received a severe impact to the back of his head prior to the Z312/3 grassy knoll shot, but from one of the acoustically determined earlier shots that missed initially with a fragment then hitting Kennedy?

thanks

[James DiEugenio]

Anthony:

Thanks for this.  I think you are correct.   Randy thinks that Tink was right the first time.  That is back in 1967.  Namely that a shot from behind preceded a shot from the front.

Tink has changed his view on this.  Under the influence of Dave Wimp, he thinks the slight forward move of Kennedy's head is really an optical illusion.  Therefore, the shot that hit JFK at this time was really from the front.

Randy does not  agree with WImp.

Can you give me more info about that bullet fragment on the outer surface of the skull? I don't think I have seen that before.

[Anthony Mugan]

Thanks James

Perhaps the best overview of the evidence around the fragment at the back of the skull is in the same book I referenced above, Thomas, D., 2014, ‘Hear no Evil’ Chp 8 (the subsection titled ‘the radio-opaque lump).

It can be seen in one of the X rays (fig 8.8a in the above ref). It originally gets a mention in the FBI report from the autopsy but doesn’t get discussed in the original autopsy report. The HSCA Forensic Pathology panel discuss it (but go off record due to concern of one member around discussing it on the record) and the HSCA interpret it as a fragment that broke off a bullet on entry, as part of their problematic overall scenario.

I quite like scenarios where there are no discrepancies between different lines of evidence, which is why I wanted to ask what the readership here thinks about this in general terms...it seems to fit together well but there could be other evidence I haven’t come across.

I’ll come back with a second question in a day or two around the interpretation of the acoustic shockwave discussed in the articles.

[James DiEugenio]

Anthony:

You are talking about the 6.5 mm fragment?

[Anthony Mugan]

James

I’d have to check through all the forensic information to be sure....In the source I was referencing it is described as being over half a centimetre in size and located 10cm above the occipital protuberance (just below the high positioned wound at the back of the head the HSCA proposed as their entry wound. Sorry not to be definitive...the medical side of this very complicated at least for my little brain. 

[Anthony Mugan]

Could I raise a second concern?

In the article there is a suggestion that a shockwave could not have been detected at Officer McLain’s location at the time of the Z312/3 headshot from the knoll. That assertion rests on using a 60 degree internal angle for the shockwave, which is described as the ‘rule of 60’ for a bullet at Mach 2. If the bullet was travelling at Mach 2 (around 2245 ft/sec at 65 deg. F and in a ‘standard atmosphere’ that would be correct.

the internal angle of the shockwave, and therefore the area in which it could be detected varies with velocity and the local speed of sound. This is usually calculated in terms of the critical angle whic is half of the full internal angle (I.e. the angle from the bullet trajectory to the shockwave). In the Mach 2 scenario 30 degrees, or half of the 60 degrees

critical angle = arcsin(1/M) where M is the Mach number or v/c where v is the bullet velocity and c is the local speed of sound. At M = 2 this does give a critical angle of 30 degrees and an internal angle of 60 degrees.

The key question is what was the actual velocity of the bullet at the closest point of it’s path to McLain’s position? That point is just before impact in this case. The velocity would drop from it’s initial value due to air resistance so the critical angle would vary and be at it’s largest just before impact when v was lowest but still supersonic.

if we take a counter scenario and estimate back the likely velocity of the bullet from the difference in timing of the shockwave and blast waves in the acoustic data we get an estimate of average velocity of 2202ft/sec +/- 104ft/sec. using HSCA test shot data to estimate the deceleration across the flight path we get an initial muzzle velocity of 2455 ft/sec and a final velocity closer to 2000ft /sec...both with similar error margins (yet again I find myself referencing Dr Thomas’s work!).
Using a mid-range estimate of 2000ft/sec would give a critical angle of 34.16 degrees and an internal angle of 68.3 degrees +/- 4 degrees in round terms (for the internal angle) when the margins of error are considered.

I would need to be a cartographer to draw the necessary maps accurately but this does seem to me to rather alter the interpretation of if the shockwave could have been detected or not.

So my question is would readers agree or are there other factors I have not considered?

thanks

 

 

[James DiEugenio]

Well Anthony,  I really don't know the answer to that one.

What was Thomas using to measure the speed of the front shot?  Barger's work or W and A?

[Anthony Mugan]

In a sense both studies, but it’s the Weiss and Ashkenazy paper that went into much deeper detail on that particular shot that provides the key data for that specific calculation. The original work by Barger et. al. at BBN covered the whole shooting sequence and provides essential data for the overall shooting sequence of course.