The thing is whatever Mignini said, the fact is he is a lawyer. His opinion on the behaviour of murderers is of no more worth than mine. On a quick look at the literature it does not seem to be supported by published studies. I note the suggestion that an expert profiler / forensic psychologist from the US says this is more characteristic of first time murderers. At least that person is an 'expert' entitled to give an opinion. There seems in this case to have been a great deal of 'amateur' psychological interpretation by the police and prosecutor but no attempt to get a qualified expert.
The whole case is riddled with this sort of thing, from fingerprint experts opining on footprints, to Steffanoni's inept crime scene investigation when her expertise is in the laboratory, to the non evidence based assertions on staging, and location of telephone calls. As the ISC said the quality of the investigation was irredeemably bad, precluding a further review of evidence at appeal court level.
What i have never understood is why none of those who believe Knox was guilty can say the investigation was of poor quality (and if it had been better irrefutable evidence of her guilt would have been found). The steep lawrence case in the Uk hinged on fibre transfer, no attempt to look for fibre transfer was made in this case.
The comments relevant to the highlighted parts are what is so good about the Italian Supreme Court motivations report which annulled Nencini's convictions - such that the kids were exonerated.
The Supreme Court author(s) of the report pick up on a theme begun with the 2013 Supreme Court panel which, back then, annulled Judge Hellmann's acquittals. Part of the reason for doing that was that, back then, The Supreme Court said that a fact-finding, lower court was not allowed to totally farm out evidence-decision-making. This was in relation to the, then, untested Exhibit 36I - potential DNA material on the knife blade.
In 2015, the new Supreme Court panel gives a summary of the issue, and cites one bit of what I assume is case law.
It turns out that (implicitly) Judge Massei's 2009 court was wrong to disallow independent DNA evaluation of Patrizia Stefanoni's work. Implicitly, Massei was wrong in law.
Massei simply substituted his own untrained opinions about DNA evidence - as did Nencini in rejecting the independent DNA analysis which the 2011 Hellmann court heard. So, legally speaking, acc. to the Supreme Court of Italy:
1) Massei was wrong not to seek the opinion of an independent DNA analyst.
2) Hellmann was wrong to allow Conti & Vecchiotti to make the de facto legal decision about whether or not testing Sample 36I should be done.
3) Nencini was wrong to discount Conti & Vecchiotti on the basis of the judge's own opinions and guesses.
You may have to read it a couple of times, but here is how the final Supreme Court frames the debate:
Marasca-Bruno Section 7 said:
This question, specific as it is, forms part of the lively theoretical debate on the relationship between scientific evidence and criminal trials, in search of a problematic balance between a theory – not insensitive to certain suggestions of interpretive stances from beyond our borders – that tends to put an increasing amount of weight on the contributions of science, even if not validated by the scientific community; and a theory that insists on the primacy of law and postulates that, in deference to the rules of criminal procedure itself, only those scientific experiments validated according to commonly accepted methodological canons may be allowed to enter.
"(T)the lively theoretical debate on the relationship between scientific evidence and criminal trials"...... That debate exposes the traditional role of Italian judges as being anachronistic:
Marasca-Bruno Section 7 said:
(This) proposes to critically reexamine the now-obsolete and dubiously credible notion of the judge as “peritus peritorum” [expert of experts]. Indeed, this old maxim expresses a cultural model that is no longer current, and is in fact decidedly anachronistic, at least to the extent that it expects to assign to the judge a real ability to master the flow of scientific knowledge that the parties pour into the proceeding;
Then to the meat of why Nencini faled in this regard:
Marasca-Bruno Section 7.1 said:
(The whole point) is, rather, about ascertaining what value in the trial the genetic investigations can have when performed in a context when the analysis and findings are not at all respectful of the regulations approved by international protocols and those which, ordinarily, must take inspiration from the scientific method.
In making implicit reference to judicial interpretation of legitimacy, the judge a quo [of the trial from which this appeal is being heard] didn’t hesitate to attribute evidentiary value to the aforementioned results (f. 217).
The assumption cannot be shared.
The 2015 Supreme Court then, further, criticises the Nencini court for accepting "judicial truth" too easily. Even a Judge cannot simply accept a scientific postulation, just because a previous court has said so:
It is the belief of this Court that the Scientific truth, however elaborated, cannot automatically be transferred into the trial to be transformed, eo ipso [of itself], in judicial truth.
So Planigale is correct - not just for the prosecutor (Mignini or Crini), but for what The Supreme Court of Italy regards as the proper way of bringing modern-day evidence into an Italian court.
What is clear is that Nencini convicted, by ignoring all of this. So says The Italian Supreme Court. So the highest court in the land exonerated the pair.