Cheers and jeers as an Italian jury has overturned Amanda Knox's murder conviction. Anderson Cooper gets worldwide reaction and has more on when she'll be able to return to the U.S. at 8 ET tonight on "AC360º". Follow updates on This Just In.
(CNN) -- American Amanda Knox and her Italian former boyfriend, Raffaele Sollecito, won their appeals of their convictions in the killing of British exchange student Meredith Kercher. Here is a guide to the Italian appeal process.
On what grounds did Knox and Sollecito appeal their convictions for murder, sexual assault, possession of a weapon, interfering with a crime and theft?
The defense sought to discredit DNA evidence linking the two of them to the killing, in which British exchange student Meredith Kercher's throat was slashed. Her partially clothed body was found in the house she shared with Knox in Perugia, a central Italian university town.
Two experts argued that DNA evidence found on the knife used to kill Kercher and on her bra clasp was unreliable and contaminated by poor handling. Prosecutors in 2009 had said there were traces of Knox's genetic material on the handle and Kercher's in a tiny groove on the blade.
Knox and Sollecito's defense teams have suggested Rudy Guede, who is already serving a 16-year sentence for the murder, could have been the sole killer.
Who made the decision?
Eight jurors -- six members of the public and two judges -- decided the case. The judges take part and vote as part of the jury: their role is to guide but not to instruct the other jurors how to vote. The presiding judge, Claudio Pratillo Hellmann, who was also one of the jurors, read out the verdict.
What were the possible rulings in the appeal?
There were three possible outcomes for the defendants:
1. Verdict is upheld: In this case, Knox and Sollecito would have continued serving their respective 26- and 25-year jail sentences. However, prosecutor Manuela Comodi had called for their sentences to be increased to life.
2. Verdict is overturned
3. Verdict is partially overturned, with a decrease in sentence (verdicts can be upheld on some counts but not others; this would result in a decrease in their sentences, which is what happened).
Does Monday's ruling mean the case is closed for good or could there be further appeals?
There will most likely be appeals by the prosecution. Both the defense and prosecution can take their case to Italy's highest court.
Both Knox and Sollecito returned to prison to complete paperwork and collect their belongings. But Knox was freed within an hour; CNN understands Knox will leave the country Tuesday morning.
Knox, 24, need not remain in Italy pending a possible appeal by the prosecution. After the ruling, the judge has 90 days to write a report on why the court reached its conclusions. The parties then have 45 days to file an appeal to the High Court, which then must schedule it, according to Luiss University law professor Nicola Di Mario.
So there'll be at least four months between the verdict and any possible High Court appeal. A High Court hearing would be very short and dependent on key technical issues and arguments, not a review of the actual trial itself, according to Di Mario.
Where would an acquittal of just Knox and/or Sollecito have left the case of the other?
That was the big question. The co-defendants appealed together, and while different verdicts could theoretically have been delivered for each of them, this was highly unlikely. A third person convicted of the murder, Rudy Guede, has already appealed to the High Court and had his sentence reduced to 16 years.
Can the defendants ever be tried again for the same crime?
After the case goes to Italy's highest court and assuming it does not overturn the appeals ruling, Knox cannot be tried again for the same crime under the "double jeopardy" rule.
What will happen if a possible appeal by the prosecution to Italy's highest court is successful after Knox has returned to the United States?
If Italy's highest court overturns the lower court's decision, it effectively revalidates the trial court's sentence, which means 26 years in prison for Knox.
Italy would then have to put in a request to U.S. authorities for extradition, and it would remain to be seen if that would granted or not. Deputy State Department spokesman Mark Toner told CNN: "Questions regarding Italian law and process are not ones we can answer. They need to be addressed to Italian authorities.
"The United States and Italy do have a bilateral extradition treaty, which has been in force since 1984. Questions about possible return to the U.S., extradition request, etc. are too speculative for us to be able to comment."
Does Italian law allow for any civil action by the defendants or by Meredith Kercher's family following a criminal case?
Yes, a civil action for damages took place alongside the original criminal trial. The family of Kercher sought $36 million in damages from the three co-defendants if they were convicted on the criminal charges. Their acquittal on the criminal charges frees them of civil liability as well.
Did the defendants face any other charges?
Knox also appealed an additional charge for which she was convicted: Defamation of Patrick Lumumba, the club owner whom Knox accused of killing Kercher. He was arrested but released after his alibi checked out. He later sued Knox for libel, winning 40,000 euros ($54,000) in damages. The appeals jury upheld that conviction and ordered Knox to pay Lumumba. It also sentenced her to three years in prison, but because she has already been held for four years, she was freed immediately.
Hada Messia contributed to this report.