One of the prosecutors in the case, Manuela Comodi, told journalists before the hearing that she thought Curatolo was a "decisive" witness. He has been a witness in two other trials, she said, and the fact that he lives outside in a public place means he sees a lot of what happens around the area.
Knox appeared more relaxed on Saturday than she had at recent hearings. Her younger sister Deanna was in court along with her stepfather Chris Mellas and friend Madison Paxton.
Deanna Knox had not seen her sister since her conviction in December 2009.
"I got to see her yesterday alone, for the first time," Deanna Knox told ABC News. "We were very excited, jumping up and down, and we kind of held each other the whole time, for an hour, basically" she said.
Asked how she found her sister after all this time, Deanna replied "Amanda is always going to be just Amanda, but every time a court date comes around she gets nervous. I can tell that about her, even if she won't admit it."
Deanna also added, however, that her sister is "very, very hopeful" regarding her appeal.
The court in Perugia set the next hearing in the case for May 21, when court-assigned independent DNA experts will present their report regarding key DNA evidence presented in the first trial.
A third person, Rudy Guede, was convicted to 16 years in prison for his role in the crime. He was tried separately from Knox and Sollecito and has exhausted his appeals.