Amanda Knox's Odd Behavior Focus of Testimony

Amanda Knox's odd behavior in the days after her roommate was found stabbed to death was once again a focal point of police testimony in her Italian murder trail today.

US murder suspect Amanda Knox, center, is escorted in a courtroom during a hearing, in Perugia,...

US murder suspect Amanda Knox, center, is escorted in a courtroom during a hearing, in Perugia, Italy, Friday, March 13, 2009. Knox, and Knox's former Italian boyfriend, Raffaele Sollecito, are being tried on charges of sexual violence and murder of her British roommate Meredith Kercher in Perugia last Nov. 2007. Both deny wrongdoing.

(Stefano Medici/AP Photo)

Police described a young woman who was calm when others were crying but at times slapped herself in the head, and at one point began shaking uncontrollably and sobbing.

Knox, a 21-year-old American, made her most forceful defense yet, standing in the Perugia, Italy court to accuse police of roughly interrogating her for hours and cuffing her on the head.

Knox is on trial along with her former boyfriend, Raffaele Sollecito, for the slashing death of her English roommate, Meredith Kercher. Another man, Rudy Guede, has already been convicted of taking part in the murder.

Much of the focus of today's testimony was on Knox's behavior, which has repeatedly been cited by investigators.

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In previous testimony, witnesses described Knox as calm and even cold just after the crime, and found her affectionate behavior towards Sollecito "inappropriate." One detective said he was surprised to find Knox doing a cartwheel in the police station.

Fabio D'Astolto, an English-speaking police officer in Perugia, told the court today that he was asked to come to the police station on Nov. 2, 2007, the day Kercher's body was found, to help question Knox.

"She seemed calm, as if nothing had happened, while everyone else was crying," said D'Astolto.

However, when D'Astolto accompanied Knox to have her fingerprints taken, he said Knox "paced up and down the hallway pretty nervously, and brought her hands to her head, hitting herself on the temples."

D'Astolto said her behavior worried him, and he offered to get her something to drink, but Knox said she was fine.

Another interpreter, Ada Colantone, described Knox's behavior two days later when she and the two Italian women who also shared the Perugia apartment were taken back to confirm that the knives found in the kitchen belonged there. Knox "started shaking," recounted Colantone. "She was shaking so hard that the coroner went over to her. She was visibly upset, and made to lie down on the couch." She said Knox also began crying.