American Amanda Knox expressed pain on Tuesday over the decision by Italy's highest court to order a retrial for her and her former boyfriend for the 2007 murder of British student Meredith Kercher.
The Court of Cassation overturned the 2011 acquittal of Knox and Raffaele Sollecito and ordered a new trial, to be held in Florence.
"It was painful to receive the news," Knox said in a statement, adding that the prosecution case "has been repeatedly revealed to be completely unfounded and unfair".
She said the new trial must include an objective investigation and a capable prosecution but did not say whether she would return to Italy for the hearings.
An initial verdict for the murder, which happened when all three were students at Perugia University in Umbria, was overturned by an appeal court after Knox and Sollecito had served four years in prison. Knox returned to her Seattle-area home and Sollecito is believed to still be in Italy.
The acquittal came after independent forensic experts said the police scientific evidence was deeply flawed and the investigation had been bungled.
Knox said in her statement: "The prosecution responsible for the many discrepancies in their work must be made to answer for them, for Raffaele's sake, my sake and most especially for the sake of Meredith's family. Our hearts go out to them."
She added: "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 in the face of wrongful accusations and unreasonable adversity."