Alright, so we know that this guy was a nut, and that he had nothing to do with killing Jon Benet Ramsey, and clearly that the media circus surrounding his arrest and extradition was among the lower moments in an low profession (at least the tabloid media, which is what most of the media turns into when confronted with something like this - lord knows they don't want to be left behind by the tabloids as happened in the past).
But, I'm somewhat interested in a couple of legal issues that happened here, the rush to judgment, and the false confessions.
On the rush to judgment front, that is clearly what happened here, if not by the DA (who kept expressing reservations as she flew him business class from Thailand), certainly from the rest of society, which had pronounced him freak, and therefore guilty once they got their hands on him. This is not quite like Richard Jewel (the alleged, presumed, and then proven otherwise Atlanta Olympic Bomber in 1996), where the case languished, suspicions increasing, and everyone who knew him pronouncing that he was just the type of person you'd expect to bomb the park ("he's a nice guy, keeps quiet, to himself, not too social...."). Before he was completely exonerated, he'd been the subject of so many smear articles and descriptions that he'll forever be associated with that bombing, even though, by all accounts, he was a hero (how fickle heroism is). More importantly, had that been a less visible case, with less scrutiny by law enforcement, he'd probably be rotting away in jail right now, the police being comfortable that he looks guilty enough, and there's no need to do more work that his lawyers would only use to manufacture reasonable doubt and get a guilty man off.
Karr's case doesn't rise to that level, mostly because, unlike Jewel, he said he was involved, and because the case was resolved so quickly and emphatically by DNA evidence showing he wasn't involved.
But, this leads to the other issue, false confessions. I can assure you that had there been no DNA evidence at all in this case, Karr would've gone to trial and been convicted largely on the basis of his statements admitting his involvement. What would the DA have said? "Why, of course he did it, he admitted it. Who would admit to doing something they didn't do?" Well, obviously a lot of people do that, for various reasons. In a large amount of the death row cases where the defendants were exonerated due to DNA proof that they were innocent, the defendants had "confessed," and their confessions had been admitted against them in trial, with devastating results. Some are browbeaten into confessing to things they didn't do, others like to brag (usually they're not as nuts as Karr appears to be, in that he was so self-aggrandize that he wanted to be associated with this case and was willing to go to jail just to have that association.
That being said, bragging about things that you have only marginal involvement in and trying to give yourself more credit than you deserve is about as common as any other form of bragging (honest or dishonest). This is why many gang members, who consider it a badge of honor to waste a few rivals with a single burst, may brag about some involvement in that shooting to their friends, even when they had nothing to do with it. And as a result, many of those statements, true or untrue, are used against them at trial with the same devastating effect. Of course the DA argues at trial that "he must be telling the truth" (and frequently he is), but they will often say at the same time that any exonerating statements should be ignored (he must be telling a lie if he denies involvement - notice the nice Catch 22?). The real problem is when those statements are used in lieu of actual evidence, and the DA relies on these often unreliable statements, coerced, bragging, self-aggrandizing, or whatever, when they don't have any actual evidence.
It didn't fly in the Karr case. It should be viewed with greater suspicion in all other cases as well. Show me the actual evidence, not just some overhyped statements that may or may not be true.