Today’s court session in the appeal of Amanda Knox and Raffaele Sollectio doesn’t seem to have put any real dynamite under anything, but it does seem to have been interesting for a few reasons.
First there was a discussion about documentation of negative controls carried out on the items of DNA evidence currently the subject of contention. The controls are significant, because a lack of evidence of them was cited as increasing the risk of contamination of the evidence in the lab, in a scientific report by court-appointed experts Carla Vecchiotti and Stefano Conti.
The significance of these documents may be somewhat reduced now, since Vecchiotti has conceded that the chances of lab contamination are, after all, not high, because of length of time between the testing of the disputed evidence and any prior testing of other evidence related to the case.
According to the prosecution, the documents were filed way back in 2008 and Conti and Vecchiotti ought to have been able to take them into consideration, it’s just that they didn’t. The defence argue that the documents were not re-filed for the appeal and that it is too late to seek their admission now. Judge Hellmann decided not to decide, and instead deferred the matter. Presumably, he will ask for the documents if he thinks they still matter at the end of the current courtroom debate.
Most of the morning session was given over to a further cross-examination of Carla Vecchiotti, this time by Fransceso Maresca, counsel for the Kercher family. It seems to have been fairly important to Maresca’s strategy to depict Vecchiotti and her collaborator Conti as having submitted a report which criticised not just the evidence in the case, but DNA evidence in general. Of course, that’s something no court could stand for, so it’s probably not a bad strategy to go for if you think you can pull it off.
It’s not really an entirely fair allegation, in my view. The central thread of the DNA report, that there were reasons to worry about the possibility that evidence may have been tainted by contamination, was reasonable. It’s a thesis that now seems in danger of corroding like an unattended metal hook, but it was right to raise it. Vecchiotti’s vice is to not want this to happen and that seems to be something that Maresca preyed on in court today, as she strayed away from sound science and onto riskier, less convincing ground.
The best example of this was her suggestion that elements of her own DNA and even (oh, the theatre!) that of Judge Hellmann, in all probability, could be discerned in the DNA printout attributed as a mixture of the DNA of Raffaele Sollecito and Meredith Kercher. Undoubtedly, that seemed to her like a good way of getting a point across. But it isn’t science, it’s rhetoric and misdirection.
As I tried to show in this post, the thing about a mixed sample is that you can usually find indications of anyone’s DNA in the printout if you really want to and you don’t know what you’re doing. I know that, because I really wanted to find Casey Anthony’s DNA in the printout we’re talking about. I didn’t know what I was doing and – hey presto! – I found it. Sort of. What I couldn’t un-find, though, was every single one of Kercher’s peaks and every single one of Sollecito’s peaks, right there, plain as day.
In case you don’t get the point, write out the names MEREDITH KERCHER and RAFFAELE SOLLECITO on a sheet of paper. You will see that every letter of CARLA VECCHIOTTI is there, except for the V and one of the Cs. But that doesn’t mean her name is there.
To put it yet another way, elements of Vecchiotti’s profile, as well as elements of Hellmann’s, probably can be seen in the Kercher/Sollecito DNA printout. But that would be true of most prinouts from a mixed DNA sample. Vecchiotti has fallen into doing exactly what Maresca is accusing her of. She’s slipped from critiquing the evidence into a low-brow critique of forensic science in general.
So, Vecchotti’s claims in this regard are not only meaningless, they’re also disingenuous. It’s a big problem for her credibility if that’s as obvious to the bench as it is to me.
And if it isn’t now, it will be at some point, because she has provided team Maresca with a singularly memorable exchange to be recalled and lambasted later in the process. Be sure of it.
On the question of the presence of Kercher’s DNA on the blade of the knife, Vecchiotti repeated the line she reluctantly gave at the last hearing before the summer break. Yes, it’s a match, you could say, but it is from a very small amount of DNA and therefore not reliable. Again, I think this is going to look like obfuscation to the judges. But only because it is. What Vecchiotti isn’t able to clarify is in what way a small amount of DNA is not reliable. From a scientific point of view, it could give rise the possibility of a false positive through contamination. But we already knew about that. Or it could give rise to “stochastic effects”, false or missing DNA peaks. But it can be seen just by looking at the DNA printouts that no such things are present. They just contain Kercher’s peaks. Again, clear as day.
I don’t think she’s fooling anyone. But it’s the fact that she is trying to that is most damaging for the defence. You could say that her point-of-view appears to small to be reliable.
In the afternoon, Patrizia Stefanoni, lead scientist in the original investigation, was, in contrast, softballed the questions by prosecution lawyer Manuela Comodi. But first she gave a presentation explaining why Conti and Vecchiotti were wrong and she was right. The detail of that presentation probably will be considered important by the judges. Unfortunately, I don’t know what those details were, so I can’t enlighten you much.
Under questioning, she explained how good the procedures in her lab were (they handled samples from behind a glass screen, apparently) and how Conti and Vecchiotti had failed to take into account how standards had changed between then and now. How can she have been expected to perform to standards that had not been set at the time? How can she be expected to have acted in the way she might do with test kits that were not yet on the market?
She admitted that plastic evidence bags were used at the crime scene after investigators ran out of paper envelopes. And there seem to have been one or two interesting new facts. Did you know they used the household fridge at the flat for storing evidence before moving it on?
But that was the easy part for her. Tomorrow, she will face questioning from the defence.
A lot of reports today have focused on a letter written to the court by Meredith Kercher’s sister, Stephanie. I don’t have much to say about that, other than that this report is the one that seems to quote from it most extensively.