Q&A: Meredith Kercher murder court case
Italy's top appeals court has overturned the convictions of Amanda Knox and Raffaele Sollecito for the murder of UK student Meredith Kercher in 2007. The decision is the final ruling in the long-running case. The pair were found guilty in 2009, then freed in 2011 after a successful appeal. A retrial was ordered in 2013 and their original guilty verdicts had been reinstated in 2014.
What are the facts of the case?
British exchange student Meredith Kercher was found with her throat cut at the flat she shared in Perugia, Italy, in November 2007.
Three people were tried for her murder. US student Amanda Knox and her Italian student boyfriend Raffaele Sollecito were convicted of murder and sexual violence in December 2009. The former was jailed for 26 years, the latter for 25.
Rudy Guede, from the Ivory Coast, was convicted and jailed for 30 years, later reduced to 16 on appeal.
In October 2011, a jury freed Ms Knox and Mr Sollecito on appeal, largely over doubts raised about the forensic evidence against them.
In March 2013 an appeal by prosecutors was upheld and a new hearing ordered. In January 2014 their guilty verdicts were reinstated by a court in Florence. Ms Knox was sentenced to 28 years and six months in jail, while Sollecito received 25 years.
Then in March 2015, Italy's top appeals court overturned the convictions again, ending the long legal battle.
Why have Ms Knox and Mr Sollecito been acquitted?
We don't know the reasons for the ruling yet.
Italy's supreme court, the Court of Cassation, will publish its reasoning in late June - 90 days after the 27 March ruling.
So who killed Meredith Kercher?
Guede's conviction still stands - but the court's ruling against him stated that he did not act alone.
The 2014 verdicts against Ms Knox and Mr Sollecito said they wielded knives, Guede held the victim down and committed a sexual assault and Ms Knox "delivered the only mortal blow".
That 2014 ruling has now been overturned - so no-one now stands convicted of acting with Guede to kill Ms Kercher.
Why were guilty verdicts reinstated in January 2014?
Prosecutors successfully argued in the Court of Cassation that the 2011 appeal hearing for Ms Knox and Mr Sollecito had disregarded important DNA evidence.
The court's judges sharply criticised the appeals court for the acquittals, saying it had ignored some evidence, considered other evidence insufficiently and undervalued the fact that Knox had originally accused local bar owner Patrick Diya Lumumba - who was later proved to be innocent.
The appeal judges were also criticised for not taking into account the judgement that Guede had not acted alone.
How could they be tried twice for the same crime?
A Court of Cassation ruling meant the 2013-14 case was technically not a new trial but a continuation of the original one.
What forensic evidence was presented?
Prosecutors pointed to a bra clasp belonging to Meredith Kercher where Mr Sollecito's DNA was reportedly found.
They maintained that Ms Knox's DNA was on the handle of a kitchen knife used in the attack, with Ms Kercher's DNA on the blade.
In addition, traces of Ms Knox's blood and footprints were found in the flat.
How did the pair plead at the 2013-14 trial?
Ms Knox was tried in absentia because Italy had no power to summon her to the hearing.
She sent a five-page email to the court maintaining her innocence and expressing her fear that the "vehemence of the prosecution" would "blind" the court.
Mr Sollecito, who attended the trial, said it made "no real sense" for him to have committed "such an atrocious act".
How did the second trial differ from previous proceedings?
Correspondents said the prosecutor in Florence, Alessandro Crini, redefined the motive of the crime.
He moved away from the drug-fuelled erotic game described by his colleagues in earlier proceedings and instead contended that the outburst of violence was rooted in arguments between roommates Amanda Knox and Meredith Kercher about cleanliness - triggered by a toilet left unflushed by Rudy Guede.
Why has the case generated so much publicity?
The case has generated global headlines as well as a number of books about the case.
The young age of both victim and defendants, the attractive appearance of Ms Knox and Ms Kercher, and the alleged sexual nature of Ms Kercher's death have all played a part in fuelling interest.
"I don't remember any case which has been as highly publicised and where the countries have taken sides,'' the noted defence attorney Alan Dershowitz told the AP news agency.
"I think it's fair to say that the vast number of Americans think she is innocent and a substantial number of Italians think she is guilty."