This is the big conceit and it has a fancy philosophical name. The knife, they argue had Ms Kercher's DNA on it; therefore it was the murder weapon and therefore it was brought to her flat. Ms Knox must have brought it there and of course it's got her DNA on it, so that proves she was doing murderous cutting and not bread cutting with it.
More deftly, there is no evidence of Ms Knox in the murder room but there are luminol hits outside, therefore it's blood. The blood must have come from the murder room so now we know that Ms Knox was in the murder room because the blood in the luminol was sort of in the shape of feet.
You can prove just about anything you like really if you do it like this. And the moon really is made of cheese - probably Pecorino.
Having just reread the part in Massei's motivation report where this whole business is discussed....
It is stunning what they accept as evidence. Massei actually does a good job describing Stefanoni's method, where she said that this sample 36B was virtually stumbled upon, and that she was aware that it was so small to begin with that her collection method was perhaps destroying other equally small samples in the process.
Massei records Stefanoni basically saying that she got incredibly lucky, finding what she found while destroying (by necessity) other potential evidence. That's how shaky all this is.
And that's before factor in the admission that the striation probably isn't there to begin with - it is most certainly not visible to the naked eye, and it cannot be photographed.
And that is before the admission that because of its small size and the destructive test which awaits it, there can only be one test - and Stefanoni chooses to do the "identity" test, instead of the "composition" test. Stefanoni comes up withe 36B belonging to Meredith, but unless it is Meredtih's **blood** then what has it got to do with the crime, rather than contamination?
But then you explained it. Crimes like this have blood associated with it, so it must be blood, because we already know that this knife was used as the weapon!!!!
So far the reasoning goes like this: we know this is the murder weapon, therefore 36B proves that this is the murder weapon.
One other thing that just occurs to me. Part of ISC's March 2013 reversal of the acquittals was because Judge Hellmann (apparently) erred in deferring his judicial role to Vecchiotti, by in essence allowing Vecchiotti to determine whether or not 36I should be tested.
Well, my read of the Massei report, is that Judge Massei in 2009 deferred all sorts of things to Stefanoni - who admits that in the process of getting something off of that phantom striation, she had to potentially destroy other evidence - because the alleged striation was so small and the "samples" she assumed was within were smaller and fragile.
Was **that** not a judicial decision, the decision to potentially destroy evidence, in order to gain **something** from her activity? Why then is not Massei reversed? Why is not Nencini reversible?