Yes, the mafia is from Italy and has been prevalent there over the years, as it has been here. But to say the Italian justice system has not attempted to control the problem the best they can (with the evidence available) and prosecute those responsible for mafia crimes is just not true. After the Ciaculli massacre, in 1963, right around the time of what is considered to be the 'first big mafia war' when a bunch of policemen were killed trying to defuse a car bomb actually meant for another mobster, almost 2000 mafioso were arrested, charged and convicted of thousands of crimes. Then in 1967 there was the huge trial of mafioso which centered on their involvement in the heroin trade (though admittedly evidence was very thin and all were acquitted). More recently there was the Maxi trial, in the mid 80s, which resulted in over 300 convictions of mafioso. Heck, in the 1920s Mussolini sent one of his top commanders to Sicily to combat the problems with the mafia, and the guy he sent was known for his tough-as-nails, iron-fisted tactics against mafioso. And these are only a couple of examples.
Just because the mafia came from Italy does NOT mean the Italian officials have just allowed the violence and racketeering to go on - the Italian government, over the years, has spent a mint trying to combat these criminals. No, they haven't 'solved' the problem yet, but has America 'solved' the drug problem here? No. That doesn't mean America isn't trying to fight it as best they can though. (Not that I believe the drug war does any good at all, and I'm for legalization/non-criminalization, but that's another story and entirely off-topic).
Finally, to compare the problem of the mafioso to Amanda Knox being convicted is ludicrous. One is a very sophisticated, clandestine group of very organized criminals with a wealth of money at their hands, the other a young female who murdered her roommate. Though they are/were, I guess, both dealt with by Italy's justice system, it makes no sense to say BECAUSE Italy's justice system has not been successful in eradicating the mafia THEN that same justice system must be entirely incompetent when trying Amanda Knox in the murder of Meredith Kercher.
ETA: Where are all the people sticking up for the boyfriend Sollecito? He's a young person just starting out in life, just like Amanda. Where's the sympathy for him? Oh wait, there is none, because he's not American. If Amanda was "railroaded" because she is American, that means Italy "railroaded" Sollecito...why? Because he's Italian? Really?