Transcript for Amanda Knox Says She Will 'Never Willingly Go Back' to Italy
It was a moment of Ron English and Amanda Knox clearly shaken by the news. An Italian court had convicted her for a second time of the murder. This morning she told Robin Roberts how she got the news. I was at my Fam lane and I actually was able defines an Italian. TV station on line. My first reaction was no and this is wrong and I'm gonna do everything I can -- to prove that it is. Nearly 28 months after being acquitted of killing British roommate Meredith curvature while both were -- in Perugia Italy. Another reversal of fortune. Amanda was sentenced to 28 and a half years in prison her Italian boyfriend of one week roughly an -- -- -- Ito was given 25 years. This really has hit me. Like -- train I did not expect this to happen. I really expected so much better from the time justice system they found me innocent before how can they say that it's guilt laden beyond a reasonable doubt. Knox vowed to keep fighting a fight that has already gone on for six and a half years. Next term lawyers will wait for the court's reasoning. And then another appeal. We have to go to the Supreme Court. We have to understand the motivation. Behind what happened and that. Happens -- within ninety days but could she be ultimately extradited to Italy are you prepared for that. I'm not I will never go willingly back. To the place. Where it. It Italy's highest court upholds this rule. Amanda Knox is a convicted -- in Italy they are going to say we want her back on our soil. The US is going to have to make it difficult decision because in most cases. Where someone's been convicted of murder. The US would extradite. Ted Simon is Amanda's US attorney and he argues she's already been found innocent how did this jury. This panel of judges come up with a different verdict come up with guilty beyond a reasonable doubt. I think to a logical mind it is somewhat incomprehensible. Because there is no meaningful difference there is no new evidence -- certainly is not any new. Favorable evidence the prosecution. -- -- was home in Seattle with her family when the verdict came. I heard the word guilty and I understood that one word in Italian and of course you know -- all of our heart sank yeah. From the start the -- is have been content and nightmare they sent their young daughter offer a dream -- abroad studying Italian. Never thinking about the vast differences between the two legal systems in Italy and the US. In the Italian system you can actually have new trials in the appellate court. And that's what happened here. If you're accused of a crime in Italy you are in big trouble guilty until proven innocent another problem here that Amanda and Rafael -- They only had alibis for each other that wasn't sufficient. It was just weeks after a man his -- that curvature was brutally murdered. Not since -- -- Ito was soon arrested. Overnight Knox became a murder suspect and an -- national media obsession. In December 2009 the two were convicted of murder after dramatic year long trial. A trial full of character accusations against Knox and full of shifting motives. There were no eyewitnesses and no physical evidence. The prosecutor -- his case on minute amounts of DNA found -- -- kitchen knife they claimed was the murder weapon. And in fact that was essentially ruled out in the most recent case -- In the end -- the first trial Knox was sentenced to 26 years in prison. The verdict devastated her family anger disbelief. -- how. Being judicial system could even come up with a verdict. Like this it's beyond me this is completely and Johnston. -- in complete shock. The Knox family made dozens of trips overseas. And spent every penny that they had more than a million dollars fighting the charges. Finally an appeals court agreed to take up the case casting debt -- on the evidence and pointing to shoddy police work. You look at -- -- it was pretty big happy -- Near the end of that second trial I confronted the prosecutor on the street you know you never minding his after his initial reluctance. The civil society -- just one on the prosecutor relented and why you ask my life and that's. -- because they killed with no motive prosecutor meaning he tells me the law dictates they must go to prison for life. -- -- dramatic decision the appeals court overturned Amanda's conviction. She flew home to Seattle. What's important from his -- -- thank you had to everyone. Who is -- do you mean. Then just as Knox was beginning her new life Italy's highest court overturned the acquittal last year -- -- it couldn't believe it. I'm gonna keep fighting this. I'm getting -- finance and I'm not gonna stop fighting this. That's -- The truth will come out. And that's all today that truth is that she again stands convicted. For Meredith purchase family what ever the courts ultimately decide this we'll never really -- over. Nothing -- still on the -- into the tree and eight. -- main beef fat that we -- reading. What happens nine. Today Amanda acknowledged the creatures pain I just want them to know that I really understand. That this is incredibly difficult but they've they have also been on this never ending thing and that. When the case has been messed up so much. Like a verdict is no longer consolation for them. And that. Just the very fact -- that they don't know. What happened. Is is horrible. One more twist today in a case that has had so many. Roughly -- so -- she -- traveling with his new girlfriend in northern Italy was stopped by police. He was allegedly trying to cross the border into Austria. His passport was taken but he was released and remains free for now. Roughly LA selected -- is in a tougher spot because he's an Italian citizen. And he doesn't how the protections of another country to go due to force an extradition -- So without the ability to force an extradition by. He could very well. Be serving time for this crime. He is vulnerable. And I don't know I don't know what I would do if they imprisoned him. Like it it's maddening. Amanda and her family had hoped their nightmare would end with this latest verdict. Instead they -- to fight to clear her name is this young woman ever going to be free of this do you think it's certainly gonna go one for a long time. With no resolution in your site. Who -- one year abroad could lead to what could be a lifetime -- deal. Right I'm gonna fight this until a variant. And done. And it's not right. And it's not fair for Nightline I'm Elizabeth Vargas in New York.
This transcript has been automatically generated and may not be 100% accurate.