Thanks Bill. I do think Grinder is unfair attributing my dismissal of the knife as "confirmation bias".
If anything, I think it is a bias for logic. Just because something is possible as "anything is possible" doesn't really mean that it should be seriously entertained.
I see no logic with this knife. None at all. And I've seriously looked at it from every angle. I shake my head that it was even pulled from Raffaele's flat. That is confirmation bias. That is the police going after a specific suspect as opposed to trying to solve a crime.
I agree with you, but I also agree with the overarching tenor of Grinder's point: IF Knox/Sollecito were indeed guilty of having used that knife in the murder, then it's reasonable to suggest that they might have opted to clean it, replace it, and bluff it out - rather than dispose of it and risk being caught in a lie.
Of course, it's preposterous to suggest that they would have elected to use this knife in the commission of the murder in any case - even IF they were indeed involved in the murder in some way (which, in my view, they were not). And the knife is - in my opinion - now totally divorced from any reliable connection whatsoever to the murder, so in fact all of this is entirely moot now anyhow.
But I think there's another interesting side point to raise here (remembering all the while that the whole issue is moot anyhow): if Knox and Sollecito HAD used the knife in the murder, and if they HAD decided to clean it and replace it, it would have been extraordinarily easy for them to have cleaned the knife sufficiently to remove every single forensic trace from it.
People tend to have a misguided opinion that, once deposited, biological forensic traces are extremely difficult - if not practically impossible - to remove. And that's simply nonsense. Especially in the case of this particular knife.
With a generally smooth, non-porous, metallic surface such as the knife blade (and the smooth, non-porous surface of the plastic handle), even a soaking and good rinsing in hot water should be enough to sluice all biological material from the knife.
If a surfectant/disinfectant such as washing-up liquid was used (and if you're trying to clean a knife after a murder, then I just suspect you might at least use washing-up liquid on it...), it's incredibly likely that anything other than a casual cleaning will remove all biological material. And again, if you were trying to clean a knife after using it for a murder, I'd think you would give it a vigorous scrubbing for quite some time, dontcha think...?
Add in even a weak solution of household bleach, and you're virtually guaranteed to have removed all biological material from the knife - even if, by some massively remote chance, there were still some DNA-containing cells remaining on the knife, even a weak bleach solution would break open these cells and denature the DNA beyond all recognition.
In short, the very proposition that Knox and Sollecito might have taken care to clean this knife - especially if it's claimed they used bleach on it as part of the cleaning process - means that it's verging on ridiculous to claim to have found biological material related to the murder upon the knife at sme point after this cleaning process. Instead, the only plausible proposition would be that Knox and Sollecito - after having used the knife in the murder and deciding to replace it in Sollecito's apartment - gave the knife only a very cursory cleaning or wiping before replacing it in the drawer (and remember that they would have been in no rush whatsoever to clean the knife). And that proposition is quite clearly ridiculous on its very face.
As another example of how water and soap gets rid of biological material, witness the shower in the small bathroom of the cottage. The prosecution claim that either Knox or Sollecito (or both) used the shower in the process of cleaning themselves after the crime. The defence would claim that Guede likely used the shower to wash blood from himself. But how much blood or other biological material was found anywhere inside the shower stall? That's right: none whatsoever. A short shower in warm water with the use of soap and shampoo would have ensured that all biological material was sluiced right down the plughole and away into the sewage system.
