Kercher's bra was found on the floor in her room, soaked in blood and with the shoulder straps torn. The part of the bra with the hooks had been cut off. This fragment of the bra was taken into evidence a month after the crime when the forensic police returned to look for it and other items they had not taken the first time.
In the meantime, the crime scened had been searched and the house turned up-side down. Sollecito's defense maintains that the late collection of the piece of bra and the earlier search of the house has contaminated that particular piece of evidence.
Under a sometimes-heated cross interrogation by the defense lawyers for both Knox and Sollecito, Stefanoni defended her methods and denied the crime scene had been contaminated.
Sollecito would have had to rub the bra hook forcefully for DNA from his skin cells to be on it, she said. Dead skin cells floating around the room do not contain DNA and would not stick, she said.
Both defendants, who have been present in court for every hearing, followed the long and often highly technical explanations attentively. Although Knox has a court-appointed interpreter she no longer relies on her, but is able to follow the proceedings in Italian without help.
Knox's step-father, Chris Mellas, was present in court today, though he does not speak Italian and does not have an interpreter. At the end of Stefanoni's presentation, before her cross-interrogation, Knox turned to Mellas with a doubtful expression, but was otherwise relaxed and sunny.
Speaking to reporters at the end of the day's hearing, Mellas said Knox had told him she thought the day had gone very well. "We aren't worried about the DNA evidence presented today," Mellas said. "It is natural for Amanda's DNA to be in the house, she lived there."
Knox's parents, from Seattle, Wash., have defended their daughter and supported her from the start, taking turns staying in Perugia so there is always someone to visit her in jail the two times a week this is allowed. They are also allowed to call her once a week.
The trial continues on Saturday with more cross-questioning of Stefanoni and another witness for the prosecution, which should wrap up its witnesses next week.