Just 15 or 20, huh? Have you thought this through?
Yes. Look at the Iran-Contra conspiracy. Hundreds of personnel took part in it, and dozens were involved in the attempted cover-up, but only a relative of top officials were driving the operation and then the cover-up. Most of the personnel were just following orders, had no idea where the funding was coming from, and were unaware of other aspects of the operation outside of their own.
Regardless, what makes you think that the "two fragments" you're concerned about were deposited by a bullet or bullets at the back of JFK's skull?
Umm, my point is that an FMJ bullet could not have deposited those fragments. A frangible bullet can deposit fragments at/near the entry site on a skull, but an FMJ bullet will never do this. In every wound ballistics test so far, no FMJ bullet deposited a single fragment, much less several, on the outer part of the skull at/near the entry wound. Not one. Never. Never ever.
When you say "the extant skull x-rays," do you mean the ones that the evil, evil bad guys didn't destroy or something?
Why do you always resort to theory and assumption when faced with hard evidence? Rather than explain why the skull x-rays don't show the low fragment trail described in the autopsy report, you resort to theoretical objections. Similarly, rather than explain the astounding fact that the autopsy report says nothing about the high fragment trail seen on the skull x-rays, you argue that, gee, wouldn't the bad guys have destroyed such damning evidence of cover-up?
You forget that the autopsy x-rays were suppressed for years, for over two decades. Only a handful of experts were allowed to view them during the two decades following the assassination. Heck, even the autopsy doctors were not allowed to review them before testifying to the WC, a fact that they found troubling. But, when independent experts were finally allowed to examine the skull x-rays, they found numerous clear indications of alteration and confirmed this via independent optical-density measurements.
So, are you going to try to explain why the skull x-rays don't show the low fragment trail described in the autopsy report and why the autopsy report says nothing about the high fragment trail seen on the skull x-rays? There are really only three possibilities:
1. The autopsy doctors committed the unfathomable, astounding blunder of confusing the high fragment trail for a fragment trail that started near the EOP and ranged upward to just above the right eye.
2. The autopsy doctors fabricated the low fragment trail. IOW, the low fragment trail never existed. The autopsy doctors fabricated it in order to explain the EOP entry wound.
3. The low fragment trail did exist but was made to disappear because it was a clearly separate trail from the high fragment trail, thus proving that two bullets hit JFK's head.