I'll stipulate that obviously there are a number of issues in trying to determine what "the truth" really is and how to deal with the sort of moral/cultural relativism inherent in evaluating what a "fair trial" means for an American (from an American perspective) in the middle of the Italian justice system. Nonetheless, these are some of the controversies that were covered by "48 Hours" (and that various internet news sources provide some evidence for) -
- The prosecutor in this case, Giuliano Mignini, was under investigation for a variety of crimes including illegally wiretapping journalists and abuse of office during the time of Knox's trial. He was later found guilty, though somehow he is allowed to work while appealing the decision. (Evidence from a British source - The Telegraph.)
- Amanda Knox claimed that she only confessed to anything because of police (physical) abuse. This might not be impressive alone, but the novelist Doug Preston has some experience with similar tactics from his time investigating his nonfiction book, The Monster of Florence. When Preston and his writing partner differed from Mignini in their opinions about who the real monster was, Mignini jailed Preston's writing partner and extremely aggressively questioned Preston... and Preston was only questioned for a few hours, Knox signed her confession just before 6am, after 14 HOURS of interrogation! (Preston is interviewed in the "48 Hours" piece, and you can find a report on Preston's experience here, from Anderson Cooper.)
- Forensic experts in the United States have serious questions about the supposed DNA evidence - matches to Knox's DNA on a bra clasp found on the victim and on a knife that could have made several of the wounds. In addition to questions about contamination and procedure, to say nothing of the innocent ways in which her DNA could have arrived on these objects, the DNA evidence itself would not be very convincing in an American court because it isn't really all that conclusive. Basically, in the US, we would dismiss evidence that isn't strong enough to rule out contamination as a cause (or peaks of DNA profiles that aren't high enough), yet most of the evidence presented against Knox would not meet such a standard. (If you want to read more about this from someone who knows more than I do and certainly explains it better, there was an article about a letter written by nine US DNA specialists questioning the evidence here on New Scientist.)
- Under Italian rules and procedures, the jury was NOT sequestered or shielded from press coverage at all. This means that the Italian press was free to call Knox an promiscuous ice queen (despite the inherent paradox in such a pairing) and publish pictures of her kissing her ex-lover and jurors saw this material! During the trial! (An article from NPR on cultural differences in the courtroom, the last part of which mentions that juries are never sequestered because of fear that doing so would separate families for a year or more.)
Psychology comes into play here in a number of ways. First, the "48 Hours" report points out that Knox's co-defendant achieved a 'directness' with the jury that she never really did, which might explain the difference in sentences. But think about the situational influences beyond guilt or innocence that might influence behavior in that situation... speaking in another language for your life, in front of the world (literally)... what could be more nerve-wracking? Shouldn't we worry about the likelihood she's a sociopath if she did NOT show emotion (that prevented her from having a level-headed conversational style speech with people who were about to decide whether she got to live) in that situation?
Again, if this trial had taken place in the United States, a number of things would have been different - the jury would have been sequestered, only evidence that couldn't be explained by contamination would have been allowed, and a variety of experts might have been able to testify and/or help Knox's team get a more desirable verdict. In the US, we have jury consultants who can help pick the ideal, most sympathetic jury. Specifically, I would hope that a defense team in an American court would be able to recognize and combat the overwhelming biases at work: the jury that enters the trial with knowledge and evidence and opinions that are already formed thanks to the press (and even if the person believes s/he doesn't have an opinion and thus forcing the defense to disprove preconceptions not formed by court-admitted evidence), the fact that this DNA evidence is not considered reliable by a variety of experts in the field, and the fact that a large number of suspects will confess to crimes they did not commit because they simply want the interrogation to stop and have become physically and emotionally drained by hours of questioning. The last point here has been shown by the number of persons who have been exonerated with the advent of DNA technology, even when those suspects had previously confessed - a whopping 25% of wrongful convictions (those where persons have been exonerated) involved false confessions. (I'm linking to data from Project Innocence, which is admittedly not an unbiased source, but I think it's presented well here and you can find similar information elsewhere online.)
Ultimately, even the Americn press was somewhat biased in its reporting as it seems far easier to find articles and information about Amanda Knox and a supposed love triangle than to find well-written pieces that challenge the assumptions and proceedings of the trial and process as a whole. That's not to say that anywhere is perfect, but I find it honestly stunning that very few people have attempted to explain some of the most simple issues and flaws in this system and that it is allowed to continue.