Its ok Mat
I think what I get from reading the link is :
It is not IMPOSSIBLE that it was animal blood - but highly unlikely
There appeared to be some human protein
It was most likely that the assumption that the blood was blood group A was incorrect
By the time the DNA testing happened there was NO blood in the moderator - but they assumed the DNA came from blood? But this expert is saying that is an incorrect assumption because the moderator had been dismantled so the DNA could have come from contamination.
He was also putting the way the "flake" of blood was tested into question.
The DNA - that was not from blood - could have been SHeilas - but the expert could only show probability.
So basically not much information proven really
Jansus it is not that complex so I will try to help you understand.
This is ignoring that the defense also tested the blood, found it tested as human blood and was group A
1) How do you know if blood is human? You do a test for human enzymes. The defense and prosecution both tested for human enzymes and found the blood they tested was human. The blood tested by the defense was microscopic drops of blood found on the first 8 baffles.
2) The next step is to test the blood components and by these components you can tell what blood group it blongs to. Both the blood teste dby the prosecution and defense found blood components that indicate it bleonged to group A.
3) The claim is that experts could potentially mess up and misidentify animal blood as human blood if they are not careful but in this instance it is unlikely that occurred because there is no evidence it occurred. They tested the blood for human enzmyes they didn't simply assume it was human.
4) There was no blood left in the suppressor by the time it was tested for DNA so any DNA results cannot have come from blood and had to come from a different DNA source. The prosecution removed all visible blood, the defense all invisible blood and this was confirmed in 1989 when a new test was conducted for the presence of blood and found none.
5) Traditional DNA tests need a sizable sample and as such when a sizable sample of DNA is found it is unlikely such would have been accidentally transferred through contamination. For instance how do you take dry saliva and accidentally transfer it to something else? How do you take dry semen and accidentally transfer it elsewhere? At best you can transer a tiny speck of such stains somewhere else and traditially DNA methods would not enable successful testing. But thanks to 9/11 a new DNA test is available. It takes a tiny speck and it replicates the DNA pattern until it is large enough to then type.
The great thing is that even a tiny speck of DNA can now be typed. But a tiny speck can arrive by contamination it doesn't necessarily arrive directly from the DNA source. So you have to be much more careful with such evidence. If peopel have nothing at all in common then their DNA should not even accidentally find its way on you, not even a speck. But specks can be innocestly transferred.
In the Amanda Knox case a tiny speck of Kercher's DNA was found on a knife in her boyfriend's kitchen. But the knife didn't match the wounds, didn't match the imprint the murder weapon made in blood andwould have a lot more DNA than a tiny speck if it had been used in the commission of the crime. Also it would have hasd scratches on the blade. The speck was not tested to see if it was blood based DNA either. So in the totality this speck of DNA was worthless. Tiny specks of Kercer's DNA was all over their flat and thus would be able to get on Knox who in turn could transfer it to other locations like the knife.
6) The jury touched exhibits that oculd have had tiny bits of DNA belonging to the victims and they potentially took apart the supporessor and could have contaminated the suppressor with tiny specks of DNA.
7) The court stated that the only way for a DNA test to determine whether the blood found by the prosecution expert and defense expert to be be group A blood was Sheila's or not would be by testing the exact blood that they tested to determine the DNA profile of the person the blood belonged to. But that blood no longer exists to be tested so ther eis no DNA test that could be performed that would ever be of any value in this case.
I tried to adress all the issues as clearly as possible.