Much of the attention has focused on Knox, 26, who has remained in Seattle during this trial, citing her fear of "the universal problem of wrongful conviction," according to an e-mailed statement she sent to the Florence court. Her representatives say she is concentrating on her studies at the University of Washington.
"We wait for the verdict, and remain hopeful," Knox's U.S. lawyer, Theodore Simon, said by telephone from Philadelphia. "But history being our guide, we know Amanda can be convicted and it is very disconcerting to her and her family. The logical position is that there is no evidence."
Knox was arrested four days after Kercher's half-naked body was discovered Nov. 2, 2007 in her bedroom in the university town of Perugia. Knox has been portrayed both as a she-devil bent on sexual adventure and as a naif caught up in Italy's Byzantine justice system.
U.S. commentators have accused the Italian judicial system of a case of misapplied justice and double jeopardy, while Italians and British observers have jumped on the image encoded in the U.S. defendant's pre-trial moniker, ''foxy Knoxy."
"I don't remember any case which has been as highly publicized and where the countries have taken sides," noted defense attorney Alan Dershowitz, who has written about the case.
"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," he said in a telephone interview.
The courts have cast wildly different versions of events. Knox and Sollecito were convicted of murder and sexual assault in the first trial based on DNA evidence, confused alibis and Knox's false accusation against a Congolese bar owner, for which she was also convicted of slander.
Then an appeals court in Perugia dismantled the murder verdicts, criticizing the ''building blocks" of the conviction, including DNA evidence deemed unreliable by new experts, and lack of motive.
That acquittal was scathingly vacated last spring by Italy's highest court, which ordered a new appeals trial to examine evidence and hear testimony it said had been improperly omitted by the Perugia appeals court, and to redress what it identified as lapses in logic.
In this trial, Judge Alessandro Nencini ordered an analysis of a tiny trace of DNA on the presumed murder weapon, a knife found in Sollecito's kitchen. In the first trial, DNA traces on the blade linked to Kercher and one on the handle linked to Knox were key to the conviction. But the appeals court trial placed the DNA findings in doubt.
The new trace tested in Florence belonged to Knox and not to the victim. The defense argued that this was further proof that Knox had merely used the kitchen knife for domestic chores in Sollecito's apartment. The prosecution, which has continued to argue the validity Kercher's DNA trace on the blade from the original trial, said the additional trace once again put the knife in Knox's hands.
The real novelty of the Florence hearings was that the new prosecutor, Alessandro Crini, redefined the motive, moving away from the drug-fueled erotic game described by his colleagues in Perugia. He contended that the outburst of violence was rooted in arguments between roommates Knox and Kercher about cleanliness and triggered by a toilet left unflushed by Rudy Hermann Guede, the only person now in jail for the murder.
Crini has demanded sentences of 26 years on the murder charge for Knox and Sollecito.
A guilty verdict would need to be confirmed by Italy's supreme court, which could take a year or more and, in theory, result in yet another appeals court trial.
For Sollecito, who has said he will be in Italy but not in court on Thursday, a guilty verdict could mean immediate arrest, house arrest or passport seizure. For Knox, the situation is more complicated.