Sorry Skip but you have not answered my questions with anything that validates your claims. Proof please!
From the COA decision:
"Mr Fletcher, the firearms expert, gave evidence to explain how blood got into the moderator if it was attached, or into the barrel if there was no moderator attached. He said that the mechanism was complicated and not then fully appreciated. However, the expanding gas when the bullet left the muzzle was under normal circumstances distributed into the atmosphere. However with a contact shot there was no opportunity for this escape and the gas would follow the bullet into the wound as it expanded. Back pressure would then build up forcing the gas back out of the wound taking with it blood and tissue which would in effect be blasted back into the barrel if there was no moderator or into the moderator if one was attached. He said that even without direct contact, the same effect might occur but only if the gap between the end of the barrel, or the moderator if attached, and the skin was less than one millimetre. He said that the likelihood of such an occurrence was to an extent dependent on the part of the body to which the shot was delivered and the amount of blood present at that point.
If the shot to Shelia Caffell, which was a contact shot to the throat, had been fired without the moderator in place, he would have expected to find blood in the barrel of the gun. If the moderator was attached it was "virtually certain" that Sheila Caffell's blood would get into the moderator. There was, he said "a very slight possibility of it not happening, but very slight".
While not mentioned in the COA opinion, he also testified that if the wound to her throat had not been a contact wound then a large amount of blood would have sprayed on the moderator or muzzle of the weapon. So the lack of much blood on the moderator and barrel further supported that the wound was a contact wound.
Also while not mentioned he testified that with the gun not at contact range very little blood would be able to get inside the moderator and it would not ravel more than a few mm deep.
The testimony was unrebutted by any defense experts.
The COA opinion also states:
"The final and most important criticism of Mr Webster is as to his findings in relation to the possibility of a mixture of blood drying in such a way that it would not thoroughly mix. We should have thought that before advancing such a theory, a scientist would inevitably satisfy himself that there was a proper basis for the theory. That might be done by some form of experimentation, by drawing upon identifiable findings in other cases of relevance or by reference to the recent conclusions of other scientists. So far as we can judge, Mr Webster has done none of these things. He rejects experimentation because he asserts that it is impossible to reproduce the exact situation that arose in this case and because he did not have available to him sufficient facilities to do anything that came close to the circumstances of this case. He pointed to one instance he had come across where a single bloodstain was a mixture of more than one person's blood, which had not completely mixed. When asked to identify the relevant case, he was unable to do so and when asked for further details it transpired that it was blood that had soaked into cloth and not, as had occurred in this case, blood that had fallen upon a non-porous surface, a wholly different situation.
Mr Webster was asked about support for his theory amongst other scientists or in published material. As to the former, he said that his theory had been "looked at by an extremely senior forensic scientist from Germany and he thinks that it is a theory worth consideration". As to the latter he referred to a paper by Stringer, Vintner, Stowel and Thomson which included the passage:
"In forensic investigations, it can be mistakenly assumed that a particular blood stain originated from a single individual. In our experience, there have been occasions when blood stains consisting of blood from more than one individual have occurred; for example crime scenes where more than one person has been stabbed. Grouping of blood mixtures in such cases can give rise to false exclusions."
We find no support for Mr Webster's theory in that passage. Of course, the danger has to be recognised or an error may occur. Mr Hayward was clearly alert to that danger and recognised in his evidence the possibility that it might have occurred in this case. He explained why he thought it was only remotely likely that it might have happened. What the passage quoted does not do is to provided the slightest support for the theory of a blood flake coming from two sources onto a non-porous surface which did not mix sufficiently for false conclusions to be drawn from grouping tests.
Mr Webster was at pains to point out that he did not have the resources to carry out testing sufficiently related to the circumstances of this case but as far as we are aware, he has not done any testing to examine the circumstances in which a small pool of blood could be created on a non porous surface to give rise to a misleading result, let alone any testing of anything comparable to the present situation.
Mr Hayward, in contrast, has we are satisfied taken some steps to satisfy himself that he is right. He started from the proposition clearly supported by evidence that within the sound moderator there would be a very turbulent motion when the rifle was discharged. This by its very nature would produce forces that would tend to mix the blood from the two sources. In addition, the unscrewing of the sound moderator to remove it involved a twisting motion through a number of complete turns, which again would facilitate mixing. Starting from this proposition, it seemed to Mr Hayward that the only likelihood of an unmixed flake of blood would be if the blood from one source dried and blood from the other source then fell upon it. That possibility was recognised and experiments were carried out to see what happened when blood was in the moderator and other shots were discharged. First the temperature of the sound moderator was established after 25 shots had been fired through it. The temperature was found to be 24.5 degrees centigrade, which is substantially less than body temperature, and hence not likely to result in any speedy drying of the blood on the moderator. The further test that was carried out was to introduce blood onto the baffles and cause the rifle to be fired to see whether the blood did in fact dry. It did not and hence the conclusion was drawn that the blood would not have dried more quickly in the moderator than on some other non-porous surface. Having regard to the time span involved, it was therefore unlikely that blood from one person would have dried before the other person was shot. It seems to us that this investigative approach is precisely the sort of experimentation that one would expect from a scientist before a theory was advanced as being capable of being relied upon.
Mr Hayward, notwithstanding this further experimentation, still acknowledges the possibility of the flake being from Mr and Mrs Bamber just as he did at trial. He still assesses that possibility as remote.
We cannot see that Mr Webster's evidence unsupported by any experimentation or other credible basis would have had any significant impression on the jury. The jury could not convict solely on Mr Hayward's conclusion in any event because he himself acknowledged the remote possibility that it was wrong. The jury could only have been sure when they considered other aspects of the case both relating to the moderator and to quite distinct issues. As to the moderator, there was the remarkable proposition raised by the defence case that Sheila Caffell having killed her family found that she could not shoot herself with the moderator on and instead of simply taking the moderator off and putting it down, went downstairs to an office, put the moderator in its proper place in the gun cupboard and then returned to her parents' bedroom where she sat or lay down on the floor and shot herself. There was in addition not merely the presence of the blood flake in the moderator but the absence of any blood in the barrel of the gun, the end of which would have been in contact with her neck when the shot was fired."
http://www.bailii.org/ew/cases/EWCA/Crim/2002/2912.htmlNeither the defense attorneys nor I have found anything in the available scientific literature to refute the position of the prosecution witnesses and likewise nothing to substantiate Webster's speculations.
Drawback effect defined: "Process that results in atomized blood drawn into the barrel of a firearm when fired at contact range".
More about atomized blood to understand what it means:
"Blood in flight: high-velocity blood
This type of bloodstain is strictly defined by the size of the resulting drops; the majority of drops in a high-velocity or atomized stain will have a diameter of less than 1 mm. A simple, cursory glance at such a stain might reveal many drops of greater diameter, and there is a tendency to give greater weight to those larger drops that tend to dominate the pattern visually. However, a detailed examination of the stain will reveal that most (>50%) are 1 mm or smaller. Such a stain requires a great force to break up the blood to this degree. In a typical crime scene setting, the only force encountered sufficient to atomize blood is that which results from a fired bullet. As the bullet strikes the source of the blood (typically a body),
it atomizes the blood into a fine spray.These small droplets have small mass and thus low momentum; they generally will not travel downrange laterally farther than two feet. Back spatter of atomized blood may also be observed, which will carry the droplets uprange in the direction of the shooter. See Figure 5."
http://www.forensic-lab.com/publications/bloodspatter.html"In the usual case of a shooting where the projectile strikes exposed skin, the energy at impact is hydrostatically transmitted throughout much of the adjoining tissue. This results in the spattering of the blood in a very fine, almost mist-like spray.
These atomized droplets of blood have a very high surface area and, therefore, cannot be projected very far in the horizontal direction."
"In addition to mist-like dropets, several larger droplets will be produced as well. A typical spray pattern, characterized as high velocity impact spatter, may be seen in Figure II-18. Note that while the vast majority of these blood spots are well under one millimeter in diameter, many larger ones are also produced."
P34 of
https://books.google.com/books?id=-m_fb580Vx0C&printsec=frontcover#v=onepage&q&f=falseThe above helps explain why it can't travel very far.
The materials available on the drawback effect do not have anything for the defense to use to try to say it would not have happened which is why the defense didn't argue that at trial or at any time on appeal. That would have been an argument used at trial had an expert been available to promote such.
I have found nothing to contradict the position of the prosecution's experts. If you want to try to search for something to use then be my guest but unless and until you find something to rebut the testimonial evidence of the prosecution witnesses there is nothing to rebut it.
