Is it unreasonable to conclude that Meredith’s alleged DNA on the knife could have got there by perfectly innocent means with no murder having been committed? We know that DNA can be transferred easily by primary, secondary or tertiary means. The quality of the DNA means it was either secondary or tertiary transfer. Amanda and Meredith shared the same toilet and living space, some sources suggest that they borrowed each others clothes. Amanda could have picked up Meredith’s DNA at the flat on her hands or from clothing on any occasion and transferred it onto the knife when cooking at Raffaeles flat.
We hear Maresca still banging on about Meredith’s DNA being on the knife but surely the burden of proof is on the prosecution to prove that the DNA was on the knife as a result of the alleged attack on Meredith and not by innocent means, this is of course something they can’t do since there was no blood on the knife! Even if the DNA was more substantial and was able to be tested twice it still offers no guarantee that the DNA wasn’t there by innocent means. The prosecution of course are absolved from having to prove any such thing!
The DNA on the bra-clasp hook seems to suggest contamination by it’s very location and by the other male DNA unidentified on the hook that doesn’t exist anywhere else on the bra. It is clear that the DNA was deposited after the clasp was ripped off. You would have to ask yourself why Raffaele would have such an interest in a detached bra-clasp considering the gravity of the alleged ongoing situation! The eventual retrieval of the bra-clasp shows it being handled by the hooks and at least one of the wearers having dirty gloves. If an eejit like me can get it, why can’t the Italian judiciary?
And you thought you'd seen the back of me!!
Hoots!
Most of the people participating in this thread can probably provide a more informed answer than me, but I'll take a shot at an answer.
I think it's very unlikely that Kercher's DNA was on that knife when the police removed it from the drawer for the following reasons.
1. The after the fact finding
Neither RS or AK DNA had been found to be in a place that it didn't belong before the authorities decide to do some more DNA testing. The police pulled a knife out of Sollecito's drawer that doesn't match a wound left by the murder weapon or the stain on the sheet and a trace of Kercher DNA is found on the knife and Sollecito DNA is found on the bra hook. That's a very big coincidence.
2. Amount below levels judged reliable for the procedures and machines used
Apparently the amount of DNA present was below the level that the machine's manufacture claimed that reliable measurements can be made at. In addition, Apparently the procedures required to collect and analyze super low concentrations of DNA were not followed so that contamination from collection or testing procedures might even be the most likely explanation in this case.
3. Unlikely selection of the location for the site of the test
Stefanoni claimed that she saw a scratch in the blade and decided to test that location for the DNA. Apparently the scratch wasn't visible to others and the idea that Stefanoni just happened to hit the location where Kercher DNA was sounds unlikely to me.
4. Failure to find DNA at the site in a retest
A second swab was tested by C & V and Kercher's DNA wasn't found.
5. Failure to publish all relevant material for the testing
This issue has continued to be controversial in this thread and I am confused, but my guess right now is that proof of control tests and the relevant raw results for the testing have never been released to the defense. If this is true, this suggests that Stefanoni realizes that her procedures were flawed and she is attempting to prevent disclosure of materials that would prove it.
6. Unlikely to remove blood and not the DNA from the blood
Chris_Halkides posted above the comments of an expert that he quoted as saying was unlikely that the knife could have been washed well enough to remove all the blood without removing the DNA as well.
Overall, I am inclined to believe the fix was in with regard to the Kercher DNA finding on the knife from Sollecito's apartment. The people involved may not have intentionally planted evidence but their actions suggested a conscious knowledge that what they were doing might produce misleading results and if those results were consistent with what they were looking for they were OK with that.
I do wish I had a better understanding of the raw data produced during the testing. I would like to have a better feel for how strong the peaks were and whether just straightforward over fitting of the Kercher DNA patterns to the results was a possible explanation also.
I am more inclined to see the tests that found Sollecito DNA on the bra hook as reliable than the knife DNA. A lot here is made of the fact that the DNA of other males besides Sollecito was found on the clasp (reasonably so since it suggests contamination), but as I recall the height of these peaks is much lower than that for Sollecito and the height of the peaks for Sollecito are much lower than the height of the peaks for Kercher. Again, I wish I understood this area better, but my sense of it is that if Sollecito's DNA on the bra hook was not a stand alone result that suggests Sollecito guilt I might be inclined to just accept it as a valid result. As it is now, it is a complete outlier. There is no other substantive evidence of Sollecito's involvement in this crime and innocent transfer or contamination in the collection/testing seem like much more likely explanations to me for the result. And for completeness, I think the low level of the Sollecito DNA peaks might have been below what is considered adequate for reliable results with the machines used
