Italy's top appeal court Tuesday overturned the acquittal of American Amanda Knox for the murder British student Meredith Kercher.

Kercher died at 21 years old in an apartment she shared with Knox in Italy in 2007.

Knox and her then-boyfriend Raffael Sollecito were prosecuted and found guilty of killing Kercher. Knox was sentenced to 25 years, while Sollecito faced 25.

They were both acquitted after serving four years.

On Tuesday, Italy's final court of appeal overturned the ruling and said both Knox and Sollecito would face a retrial.

Knox is currently living in Seattle.

Rudy Hermann Guede, a drug dealer who knew Knox, was convicted and given a 16-year sentence.

Knox's lawyer Carlo Dall Vedova told the Associated Press that if the court ordered another trial and the conviction is upheld, Italy could seek her extradition from the United States.