Perugia: An Italian public prosecutor said on Tuesday he would appeal against the acquittal of US student Amanda Knox for the murder of her British housemate Meredith Kercher, whose disappointed family vowed that their search for justice would go on.
"We will appeal," prosecutor Giuliano Mignini told Reuters in a telephone interview. "The (higher) court will decide whether to confirm the first sentence or the second sentence."
The prosecution will appeal to the Court of Cassation, Italy`s highest appeals court.
As Knox waited at Rome airport for a flight to London and then on to Seattle, Kercher`s mother and siblings held a news conference in Perugia and said their ordeal would continue as they looked for the truth about the killing four years ago in the central Italian city.
Kercher`s sister Stephanie said they would wait for the written explanation of the acquittal verdict in the hope that all the killers would eventually be found.
"Once we`ve got the reasons behind the decisions for this one, then we can understand why they have been acquitted of it and work toward finding those who are responsible," she said.
"That`s the biggest disappointment, not knowing still and knowing that there is someone or people out there who have done this," she said.
Ivorian drug dealer Rudy Guede was jailed in 2009 and is serving a 16-year sentence for his role in the murder. But investigators believe more than one person was involved in holding Kercher down while she was stabbed and had her throat cut.
As she prepared to leave Italy after four years in jail, Knox thanked supporters who believed in her innocence.
"I will always be grateful for their courageous commitment ... (grateful) to those who wrote to me, to those who defended me," she said in a letter to an Italian-American foundation, published by Italian news agency Ansa.
Seattle native Knox and Italian computer student Raffaele Sollecito had appealed against a 2009 verdict that found them guilty of murdering 21-year-old Kercher during what prosecutors had said was a drug-fueled sexual assault four years ago.
Knox, who broke down when she was cleared on Monday night, was guarded by police in an airport restaurant in Rome as she waited for her flight to London.
British Prime Minister David Cameron on Tuesday urged people not to forget Meredith Kercher`s parents.
"Those parents ... had an explanation for what had happened to their wonderful daughter, and that explanation isn`t there ... I think everyone today should be thinking about them and how they feel," he told ITV.