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 a 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 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, while 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.