For Amanda Knox 2011 was the year that life began -- the culmination of four grueling years spent locked away in an Italian prison. Following an appeals court ruling that -- -- Knox returned to the US... See More
For Amanda Knox 2011 was the year that life began -- the culmination of four grueling years spent locked away in an Italian prison. Following an appeals court ruling that -- -- Knox returned to the US relieved and thankful but earlier today came an Italian Supreme Court decision. It all but -- and -- -- long fight for return to normalcy will rage on ABC's Neal Karlinsky reports. The -- not -- -- four year old Seattle's Tacoma. It's even in a case filled with more twists and turns and Hollywood movie. -- and -- Thank you. We're being -- -- -- the decision hit like an earthquake. At 2 AM back home in Seattle Amanda Knox now at 25 year old college student at the University of Washington. Got the news that her life was about to take yet another painful turn. Just over the -- jobs and please. Overnight there she's also been strong in the sense that she wouldn't fight begins to -- this up for the. It was Italy's highest court its Supreme Court that made the stunning reversal. Amanda Knox will face a new trial for murder though the exact reasons remain unclear it won't be spelled out by the court for another three months. In his statement Knox said the court's decision was painful and completely unfounded and unfair. No matter what happens my family and I will face this continuing legal battle as we always have confident in the truth and with our heads held high. There is no evidence. During never was any evidence and there never will be any evidence so they remained. Cautiously optimistic. They even upon this really -- and to the appellate court. That the same result will occur she will be determined. To be not guilty. One immediate question. How could this happen after all Knox famously served four years in an Italian prison for the murder of a college roommate. Was freed on appeal in the dramatic and emotion charged hearing. Then came home to Seattle a year and a half ago to start a new life complete with a reported four million dollar book deal. I'm really overwhelmed right now. I was looking down on -- play. And it seemed like everything wasn't real. So how can according Italy suddenly just change its mind in this country once there's -- not guilty verdict the case is over. But in Italy prosecutors. Can appeal and they did appeal and they want. And the High Court objectively said. Try this case again. Put simply the Italian judicial system is very different than our own even if she is convicted again that can be appealed as well. She's worried she's -- workers dozens. This is to use if a woman kicked around and go into the senate committee go vote -- -- -- it's. -- good. Horizon -- would have decided. Knox came to -- yet to study Italian in 2007. Knox and her former boyfriend what found guilty Amanda Knox found guilty of murder in Perugia Italy -- -- of sexually assaulting and killing miss -- It was just weeks after her arrival that Meredith culture was brutally killed. Knox and her then boyfriend of just one week -- also lets you -- Were soon arrested overnight Knox became a murder suspect and international media obsession to. The tragedy rather that Landon now six. In December 2009. -- were convicted of murder afterward dramatic year long trial. Knox was sentenced to 26 years in prison so let's Ito to 25 years. The verdict devastated her family. Which made dozens of overseas trips and spent everything they had more than a million dollars fighting the charges. Anger disbelief. Klein how. A judicial system could even come up with a verdict. Like this it's beyond me this is completely and Charleston. I'm in complete shock. After a thousand hours in court 47 months locked in prison Knox pleaded her case in a last ditch appeal I -- yeah. I'm -- with my life for something I haven't done she said I am not what they say I am in a stunning move the appeals court agreed. So they have been removed happy -- that it was pretty -- death. Citing shoddy police work and the lack of forensic evidence. And throwing -- conviction in an emotionally overwhelming. Verdict. What's important from his -- -- thank you to everyone. Who's probably -- do you mean. Who's defending didn't mean -- what are my family. Since her return home Knox could be seen on the streets of Seattle getting coffee between creative writing classes. She has a boyfriend and lives in her own apartment. She has plans to. Amanda Knox wants to make a living as a writer. But that we'll have to wait for life yet again has been put on hold no matter what happens in this case I think it's very unlikely. That Amanda Knox would be forced to go back to Italy. Amanda Knox is chronicle of -- ordeal will be published next month. Long before the final chapter of her own real life drama is anywhere near finished. I'm Neal Karlinsky for Nightline. In Seattle. So Amanda Knox is memoir waiting to be heard Adam that's going to be released April 30 and ABC news will air her first interview with Diane Sawyer that evening at 10 PM --
This transcript has been automatically generated and may not be 100% accurate.