This was discussed ad nausium months ago. For ages people made the argument you are making. I would reply, yes, but perhaps there were reasons why that knife was chosen. Why assume that the police acted inexplicably? Perhaps, I joked, all the other knives were butter knives.
Eventually Charlie Wilkes emailed me a photo of the draw. It contained the kitchen knife we are discussing and a bunch of ordinary table knives.
It doesn't have to be connected by all three. In any case, why does there have to be only one knife? That's why I capitalized "THE".
As for the list of required evidence.. how about:
1. There is physical evidence on the knife linking it to the crime
2. That the handling of the knife isn't such that any physical evidence found on the knife is too unreliable to be considered.
I don't understand why we are arguing about Guede. The evidence against him is fine and I'm not seeking to diminish it. That there may be less evidence against the other two, or that it may be more complicated and interconnected evidence is neither here nor there.
It's true that RS's drawer had only one sharp knife, but the kitchen drawer at the murder flat had many. Doesn't that make you think that the police needed evidence from RS's apartment so that they could link him to the crime?
Why does there only have to be one knife? To believe that multiple knives are required to commit a murder is implausible.
I mean a 120 pound woman was killed, not a Rhino or a Grisly bear.
The list is a list of possible evidences that could make the knife equal to ONE valid piece of evidence.
1) The knife was at the scene of the crime when the murder took place. (In LCN DNA cases, this should be required)
2) The knife inflicted the wounds.
3) The suspect used the knife to inflict the wounds. (DNA on the knife isn't really 99% proof)
4) The knife had the victim's DNA on it (Both good DNA and blood should be required for 99% proof)
5) The knife had the victim's blood on it.
6) The forensics lab was very, very clean and very very good (Necessary for LCN DNA)
7) None of the police were motivated to please someone that could effect their raises or promotions (Necessary all the time)
One of the first three on this list should be required. Perhaps not all three if one is super solid – but none are. One of either number four or five on that list must also be required. The validity of the evidence requires that one or both of #4 or #5 be really solid. If #4 and #5 are super solid, then #6 isn’t required. #7 is an absolute must. #7 must be established.