Q&A: Amanda Knox faces retrial - what happens if she's guilty?

What will be the impact of moving the case from Perugia to Florence?

In theory, not that much. The first appeal has to redone in another city, simply because it can’t be heard by the same judges as the last one – and in Perugia there is only one appeal court.

A bigger influence on the outcome will be the detailed motivations of the six judges at the supreme court of Cassation, who ordered the retrial. Their thoughts will be published in the coming weeks or months.

With all that’s been written about the case is there any hope of a fair trial for them?

The anglo-saxon way of thinking says all the publicity and gossip surrounding the accused would make a fair trial difficult. There are no contempt of court laws here preventing the press writing about the trial participants. But in Italian courts the presence of two judges in the jury of six is supposed to provide mitigating professional guidance to the four lay members.

What will happen if Knox is found guilty and refuses to return to Italy, particularly as such a retrial would not be allowed under US law?

Given the relative rarity of extradition requests between the US and Italy, and the peculiarities of this high profile case, we are, in the words of international law expert Rebecca Shaeffer of Fair Trials International, “entering hypothetical territory”.

She said that because Ms Knox would have effectively been tried twice for the same crime, the US authorities would probably cite the double jeopardy rule in blocking her extradition. Article 6 of the 1983 bilateral treaty between the two countries states that “extradition shall be denied when the person sought has been in jeopardy in the requested State for the same offense” (in Italy, the double jeopardy rule doesn’t apply before the supreme Cassation court rules on a cases).

“But if Ms Knox were definitely convicted and extradition were refused by the US, there are other things that Italy might do,” she said. “As a country seeking to extradite the person it might contact Interpol for help or use a red notice (and international arrest warrant). This means she would be safe in the US territory – but not if she travelled abroad. She could be seized were another country minded to act on the request by the Italian authorities. So travelling would be the biggest danger for her.”

Why were the convictions overturned last time ?

Senior appeal Judge Claudio Pratillo Hellman said prosecutors had failed to provide the court with a murder weapon, a credible motive, a precise time for the killing, reliable DNA evidence or even sufficient proof that Ms Knox and Raffaele Sollecito, had been at the location where the crime occurred. Most crucially, an expert review ordered by the appeal court in the summer had discredited crucial DNA evidence, saying there were glaring errors in evidence-collecting and that the amounts of DNA said to incriminate Ms Knox and Mr Sollecito fell below internationally accepted thresholds.

Why might this trial be different?

The views of the supreme court judges on the how the law was not properly applied in the appeal case will undoubtedly influence the outcome. Their reasoning is not yet available. But already there is speculation that the importance placed on the review of the DNA evidence in the first appeal, may prove less decisive in the retrial.

What have Knox and Sollecito been doing since their release from prison in 2011?

Knox sped back to safety in Seattle in the US and managed to get a book deal. The memoir, called “Waiting to be Heard”, is due to be published on April 30 and will coincide with her first television interview on the ABC network.

She is currently studying at the University of Washington. Mr Sollecito, a computing graduate, is currently robotics at the University of Verona in northern Italy. His 2012 memoir, "Honor Bound: My Journey to Hell and Back with Amanda Knox," casts doubt over where Knox was the night of the murder and even accuses her of "bizarre behaviour".