FLORENCE, Italy (AP) -- Former American exchange student Amanda Knox spent four years in jail in Italy, from her arrest to her conviction in her first murder trial through her successful appeal. She's now facing a second appeals trial, along with her former Italian boyfriend Raffaele Sollecito. Here's a road map to help understand where the Italian court system is going next:
FIRST TRIAL, SECOND TRIAL, THIRD TRIAL
Knox and Sollecito were convicted in 2009 of murdering British student Meredith Kercher, whose throat had been slashed the night of Nov. 1, 2007. Knox was sentenced to 26 years, including one year for a slander conviction for wrongly accusing a bar owner of the murder, while Sollecito received 25 years.
An appeals court overturned their murder verdicts, while confirming Knox's guilt on the slander charge and raising that sentence to three years. Knox, who had spent four years in jail during the investigation and the trials, was free to return to the United States, and she did.
In March, Italy's highest court vacated the appellate court ruling in a scathing decision that blasted it for "deficiencies, contradictions and illogical" conclusions. It ordered the case back to appeal, noting specific weaknesses such as the failure to hear one witness or to test a minuscule trace of DNA on the handle of the presumed murder weapon.
The new appeals trial in Florence began in September.
THE THIRD APPEAL
Knox is now 26 and Sollecito is 29. She has remained in the United States but submitted a written statement to the court, denying that she was a killer. Sollecito has attended some hearings and addressed the court in Florence. All the evidence is being weighed again at this trial.
The judge in the Florence appeals trial ordered additional DNA testing on the tiny DNA trace on the presumed murder weapon. The trace had been previously been deemed too small, but the high court noted advances in technology. The test indicated the DNA on the handle belonged to Knox. The defense considered the finding a victory, because it failed to provide independent proof that the knife found in Sollecito's drawer was the murder weapon.
Still, the prosecutor argued in his closing that a trace of DNA found on the blade, which was key to the lower court convictions, belongs to Kercher. That finding was put into question by experts in the appeals trial. The prosecutor also backs the validity of a DNA trace on a bra clasp that has been attributed to Sollecito. Sollecito's defense has argued that the evidence was compromised.
Prosecutor Alessandro Crini has demanded a 26-year sentence each for murder for Knox and Sollecito, and wants Knox's slander sentence increased to four years. In his closing arguments, the prosecutor also shifted the murder scenario from an erotic game gone awry, as was claimed in previous trials, to a long-standing disagreement between Knox and Kercher over cleanliness that exploded in violence triggered by a dirty toilet.
Raffaele Sollecito's defense makes its closing arguments on Thursday. Both sides will have a chance for rebuttals Jan. 20. The panel of 10 -- two professional judges and eight lay jury members -- will begin deliberations on Jan. 30. A verdict is likely the same day, but the timing is uncertain.
IF THERE IS ANOTHER CONVICTION
If Knox is convicted, the verdict would still need to be confirmed by Italy's highest court to be final, a process that can take months. Then the Italian justice ministry would have to request her extradition from the U.S. to serve the sentence, something it's likely to do given the severity of the crime. As for Sollecito, the sentence could be started much more quickly since he is in Italy, pending formalities.
Legal experts say the United States might challenge the extradition on the basis of the U.S. legal principle of double jeopardy, which bars trying someone for a crime for which they have been acquitted. But since Italy's high court never confirmed the acquittal, a necessary step to making it final, the wrangling could be protracted.
The case could be further bogged down if Knox and her legal team appeal any guilty verdict to the European Court of Human Rights, whose rulings would be binding on Italy. If it rules that the Italian justice system did anything in violation of the European Convention on Human Rights, then the court could in theory order a retrial, or tell Italy to change its laws. In most cases, the court only imposes fines, or calls for subtle changes. Knox has already appealed the slander conviction to the European court.
THE THIRD DEFENDANT
A third defendant, Ivory Coast-born Rudy Guede, was convicted in a separate trial of sexually assaulting and stabbing Kercher. His 16-year sentence, reduced on appeal from 30 years, was upheld in 2010 by Italy's highest court, which said he had not acted alone. Guede, a drug dealer who fled Italy after the killing and was extradited from Germany, acknowledges that he was in Kercher's room the night she died but denies killing her.
Prosecutors have argued that the murder was carried out by more than one person, citing the multiple stab wounds, which they allege could be from different knives.