(CNN) -- An Italian appeals court convicted former exchange student Amanda Knox and her ex-boyfriend Raffaele Sollecito on murder charges Thursday night.
Prosecutors said the couple had killed Meredith Kercher in November 2007. They were convicted two years later of murder, but those charges were overturned on appeal in 2011.
A judge said Thursday that Knox was sentenced to 28 1/2 years in prison. Sollecito's sentence was 25 years.
It is unlikely Knox, who lives in Seattle, Washington, will return to Italy to serve additional prison time because U.S. law dictates that a person cannot be tried twice on the same charge, a legal expert told CNN.
Following the verdict, Knox released this statement:
"I am frightened and saddened by this unjust verdict. Having been found innocent before, I expected better from the Italian justice system. The evidence and accusatory theory do not justify a verdict of guilt beyond a reasonable doubt. Rather, nothing has changed. There has always been a marked lack of evidence. My family and I have suffered greatly from this wrongful persecution."
The lead judge has 90 days to write his arguments behind the jury's ruling. Once that is out, lawyers have 90 days to appeal.
Kercher, 21, was found partially naked in a pool of blood in the house she shared with Knox in the picturesque town of Perugia, where both women were exchange students.
Knox has said she is afraid to return to Italy, where she spent four years behind bars.
"I will become ... a fugitive," she told Italian daily La Repubblica this month, when asked what she would do if she was found guilty.
Italy's Supreme Court in March overturned the pair's acquittals, saying that the jury did not consider all the evidence and that discrepancies in testimony needed to be answered.
The case was sent to a retrial in Florence.
Dressed in a purple sweater with sunglasses nestled on his collar, Sollecito made it to the tribunal for the morning session and was expected to return for the verdict, but his attorney, Luca Maori, said Thursday evening that Sollecito would not be coming back to court.
The retrial began last September, refocusing international attention on the case that grabbed headlines in Italy, Britain and the United States -- but neither Knox nor Sollecito were present in court.
It has renewed questions about the effectiveness of Italy's justice system given widespread doubts over the handling of the investigation and key pieces of evidence.
Prosecutor Alessandro Crini has said both Knox and Sollecito should be convicted and handed a 26-year sentence for homicide, with an additional four years for Knox for slander.
Both have maintained their innocence.
With little change in the case details over the years, it is not clear how presiding judge Alessandro Nencini will rule.
Regardless of the decision, both sides will have the opportunity to appeal that verdict to Italy's Supreme Court. That process could take months.
If Knox is ultimately found guilty, Italy could request her extradition from the United States, but it is unclear what would then happen.
Knox, 26, and Sollecito, 29, were convicted in 2009 of killing Kercher, who was found with more than 40 stab wounds and a deep gash in her throat.
Prosecutors say she was held down and stabbed after she rejected attempts by Knox, Sollecito and another man, Ivory Coast-born Rudy Guede, to involve her in a sex game. Guede is the only person still in jail for the murder and many aspects still remain unexplained.
Speaking on Thursday, Knox's defense team asked for an acquittal.
Lawyer Carlo Della Vedova said the team was "serene" about the verdict because they believe the only conclusion from the case files is an acquittal.
Knox has always denied murdering Kercher and has maintained she is not guilty in a written statement to the Florence court.
"I must repeat to you. I'm innocent. I did not rape, I did not steal ... I did not kill Meredith," Knox said in a lengthy e-mail presented by her lawyer to the court in December.
Sollecito was in the Dominican Republic at the start of the retrial but returned to Italy.
In November, he took to the stand to make a spontaneous declaration, saying the charges against him were "absurd."
"For me, it's a nightmare that goes beyond imagination," he said of what he's been through.
'No one remembers Meredith'
A lawyer for the Kercher family, Francesco Maresca, said the victim's brother and sister, Lyle and Stephanie, would attend court to hear the decision.
The case has dragged on for more than six years, frustrating attempts by Kercher's family to discover the truth about her death. The three trials have done little to clear up mysteries surrounding the details of the murder.
"They are tired of this long trial and they want justice," Maresca said.
The Kercher family welcomed the retrial ruling, Maresca said in March, adding they believed the ruling that acquitted Knox and Sollecito was "superficial and unbalanced."
They believe more than one person was in the room when Kercher was killed, he said.
"No one remembers Meredith, while the two defendants write books, speak to the media and earn money," Maresca told the court in closing remarks last month.
Ferguson advocates for Knox
One person who has been advocating for Knox is Ryan Ferguson -- the Missouri man who walked free last November after being imprisoned for nearly a decade. He was wrongly convicted of murdering a newspaper editor, and a state appeals court overturned his conviction.
"We kind of had this connection in the sense that we've been through this justice system ... It's relatively the same. We've been through this, and there's not a whole lot of people" who've had the same experience, he told CNN's "New Day."
"So it's cool and we can kind of just talk to each other. She wanted to reach out and say if you need to talk to anybody, if you need any help, I'm here for you. If not, I completely understand. So that's how we began communicating."
Asked about Knox' current state of mind, he said she's staying positive.
"She seems to be doing very well. I'm impressed with her. It's so daunting at this time," he said. "Within 48 hours she should know her fate. You can't start living life until they actually clear you and until you're free essentially. So I'm amazed how she's doing. She's working hard on school and continuing life the best she can. She believes the courts are going to do the right thing based on the facts. I agree."
-- CNN's Livia Borghese contributed to this report