30/09/2013 05:29 BST

Amanda Knox Case: Retrial For American Over Meredith Kercher Murder

Amanda Knox is set to be tried again for the murder of British student Meredith Kercher, but the former student will remain in Seattle because she fears to go back to Italy.

Knox and her Italian ex-boyfriend Raffaele Sollecito were found guilty of the brutal 2007 murder of the Leeds University student four years ago, but acquitted in 2011 and Knox returned to the US.

Amanda Knox appears on NBC News' 'Today' show

In March of this year, their acquittals were overturned by Italy's Supreme Court, because of issues with the DNA evidence.

Hours before the retrial in the Tuscan city of Florence was set to begin, the Kercher family issued a veiled plea for Knox not to visit their daughter's grave.

Knox is not required to be present for the retrial, but has said in multiple interviews she does not intend to return. Italy could request her extradition if she is found guilty again, but in practice it is unlikely a request would be granted.

"I was already imprisoned as an innocent person in Italy," Knox told America's NBC television. "I just can't relive that."

"I thought about what it would be like to live my entire life in prison and to lose everything, to lose what I've been able to come back to and rebuild. I think about it all the time. It's so scary. Everything is at stake.''

"I have plenty to fear because I was already imprisoned wrongfully," she told ITV's Daybreak, when she was quizzed on why feared a return if she was innocent. "This, as an innocent person, is the ultimate nightmare."


Amanda Knox Retrial Welcomed By Meredith Kercher's Sister: 'There Are Still Unanswered Questions'

Amanda Knox Tells Daybreak She Will Take Lie Detector Test (VIDEO)

Amanda Knox 'Would Like To Visit Grave Of Meredith Kercher"

Knox has previously expressed a desire to visit her former flatmate's grave.

But, in a statement issued through their Italian lawyer, Kercher's elder sister Stephanie said, carefully: "It took us as a family nearly five years to even begin to feel ready to lay Mez to rest and it is still extremely painful now.

"However, she now has a place near to us that we and her friends can visit to take flowers and spend time. Her grave is now her safe place to sleep in peace and be with us and we hope that is respected by all."

"For me, I hope that despite the fact that the case continues, she is resting in peace but, knowing Mez, she will be fighting until the end."

Prosecutors originally alleged that Kercher, who was stabbed repeatedly and had her throat slit, died in a drug-fuelled sex game that went wrong. The supreme court has said that particular theory should be re-examined.

Knox insists she and Sollecito were at his flat, smoking marijuana and watching a film.

Another man - Rudy Guede from Ivory Coast - has been sentenced to 16 years for the killing.

The supreme court said it needed to examine "numerous deficiencies, contradictions and manifest lack of logic" from the first appeal. Judge Alessandro Nencini will preside over the new hearing.