Amanda Knox Tells Jurors She Fears Being Branded a Murderer

Knox's family says she's excited about going home, but "scared" of a conviction.

PERUGIA, Italy Dec. 3, 2009— -- In a tremulous voice that at times broke with emotion, Amanda Knox told jurors who will decide her fate within the next 24 hours that she felt "vulnerable" before them at this "important moment."

Knox's statement concluded her defense at the end of the 11-month long Italian murder trial that will end Friday. The six person jury and two judges who will begin deliberating Friday morning are expected to stay at it for 12 to 18 hours to have a verdict by Friday night.

The Seattle college student, who has already spent two years in jail, could be sentenced to life in prison if convicted of murdering roommate Meredith Kercher Nov. 1, 2007 with the help of two men, ex-boyfriend Raffaele Sollecito and Ivory Coast native Rudy Guede.

"I have thought in these days about what I wanted to say and I had a question, which I wrote down, that a lot of people have asked me: How can you stay so calm?" Knox said to the jury in the Italian she has improved during her years in prison. "The first thing to say, is that I am not calm."

"I am afraid of losing myself. I am afraid of being defined as something I am not, and by actions that are not mine. I am afraid of having a mask of a murderer forced on to my skin," she said with a shaky voice but with some obvious determination.

Click her for complete coverage of Amanda Knox case

Referring to the two years she has already spent in jail, Knox said, "I can confess that I feel confused, sad, frustrated."

She said people have asked how she has been able to not pull her hair out, get depressed or destroy her jail cell.

"In these situations I breathe, and try to find the positive in the important moments," she said as her voice quavered. "And I know this moment is one of those moments, because in this moment... a real decision is being made about a fact. It must be understood."

Her voice broke as she continued and said to the jurors, "And I feel more in touch with you, more vulnerable in front of you. But I have faith and am sure of my knowledge."

Knox thanked several people for support over the last two years including her lawyers, "my family, my friends who are the reason... that I am able to bear it." She even thanked the prosecutors "even if they don't understand me... because they are trying to bring justice to an act that has taken someone from the world."

"The important thing now," she concluded in remarks directed at the jurors, "is that I thank you because it is your turn now and so I thank you. Okay."

Amanda Knox's Co-Defendant Says He Had No Motive for Murder

The Knox case has been heavily covered by the press since the murder occured on Nov. 1, 2007, but as the trial heads to a climax it has become intense. Journalists and cameramen jammed the small courtroomand tiny press room. Reporters shouted "Amanda, Amanda" as she entered court and so many camera flashes went off today that the courtroom was lit up.

Despite the pressure, Knox has been smiling and relaxed in recent days. Today, however, she appeared more serious as the trial nears an end and a verdict looms.

Knox's 20-year-old sister Deanna, who was in the courtroom for the last two days, told ABC News' Elizabeth Vargas in an interview to air Friday on "20/20" that her sister is torn between excitement at the prospect of going home for Christmas and fear of a conviction.

"She told me a little while ago she was really excited about the possibility that she could be flying home with us," Deanna Knox told Vargas.

At the same time, Knox is worried. "I know she's scared. She's afraid because her life is in other people's hands," her sister said.

Knox's father Curt also mentioned Knox's fears to Vargas.

"I'm sure she's going to be errified. She's going to be scared it's going to go wrong," he said. "She's innocent, sitting in jail accused of a crime she did not commit. So she is definitely scared."

Earlier, Sollecito made his final statement, telling the court that he had no motive to help kill Knox's roommate, but a prosecutor countered that a motive isn't necessary for conviction and said there is a lot of unexplained violence these days.

Sollecito, 25, was Knox's boyfriend at the time of the murder. He is accused of helping to kill Meredith Kercher in a booze and drug-fueled fury that was allegedly sparked by Kercher's criticism of Knox's cleanliness and her habit of bringing boys home. Prosecutors described Sollecito as a follower of the then-20-year-old Knox, calling him "Amanda-dependent."

Sollecito softly told the court today that he was living through an "absurd affair about which I know nothing."

"I would like to understand today, because it is not at all clear, why I should have participated in a murder," he said. "Not having found a motive to explain what made me kill, they said I was a sort of dog on a leash – Amanda-dependent.

"I had only known her [Knox] for a few days. I certainly cared for her, but they were the very first days (of our relationship) and there was no dependent relationship there. If Amanda had asked me to do something I did not agree with, I would have said no. Imagine if she asked me to do something as terrible as killing a girl," he said.

Sollecito ended his defense by saying, "I did not kill Meredith. I was not in that house that night. I hope the real murderer comes forward and confesses. I still have faith in justice. For me it represents everything. Thank you for listening to me."

It was the latest assault by the defense on what they said was an unconvincing motive, that Knox got Sollecito and uede, to help kill her "prissy" roommate who had criticized her. One prosecutor described Knox as so full vengeance that she was a "coiled spring."

Prosecutor Says Motive Not Needed for Conviction

Guede has already been convicted of taking part in the murder and has been sentenced to 30 years in prison. He is appealing his conviction.

Prosecutor Manuela Comodi concluded the prosecution's case today by saying " a motive is not necessary to prove a murder."

"The motive exists, and if you do not want to listen to it, then ok.... It is logically conceivable. But even if the court decides that the motive does not stand up, it does not mean legally that the defendants cannot be found guilty," Comodi said.

"Why did they do it? I ask myself the same thing," said Comodi. "Why do normal kids set fire to a homeless man? Why does a girl get her boyfriend to help kill her parents? Why does a mother kill her child?" she said referring to well publicized cases in Italy in recent years.

"We live in era of 'violence without a plan' for which we have no explanation," Comodi said.

Comodi zeroed in on the one piece of evidence that allegedly places Sollecito at the crime scene, a clasp torn off of Kercher's bra that has Sollecito's DNA on it. Sollecito allegedly cut it off during a sexual attack on Kercher before Knox allegedly slashed her throat with a knife.

Using a bra identical to the one Kercher wore, Comodi strapped it to a microphone and pulled it with a finger to show how Sollecito allegedly pulled it back so he could slice it off, and leave his DNA on the clasp.

Sollecito's lawyer has argued that the clasp wasn't found for 43 days and in that time Kercher's room was thoroughly searched and items moved around. During the extensive search, the crime scene and possibly the bra clasp were contaminated, they stated.

But police forensics experts can tell when evidence has been contaminated and the clasp was not contaminated, Comodi said.

She also countered the defense's claim that Knox and Sollecito did not act like killers when they called the police after finding Kercher's body.

"The perpetrator of a crime is known to give the alarm in order to avert suspicion from himself," a mechanism that does not require a criminal mind, she said.

Amanda Knox Could Face Life in Prison

Comodi closed the prosecution's case by comparing the stories of Sollecito, Knox and the prosecution to the children's story TheThree Little Pigs. Sollecito and Knox built flimsy stories of straw and sticks, she said.

"The third house, solid, and built brick on brick, is the prosecution. Not even one piece of the puzzle is missing," she said.

A lawyer for Kercher's family also spoke to the jury today, asking them to convict Knox and Sollecito of murder.

Francesco Maresca said he wanted to "remind the jury one more time that we are speaking of a victim who was just a 21-year-old girl found dead at the hands of young people of her own age."

He said that logic pointed to Knox and Sollecito as the killers who had already sexually assaulted Kercher.

"Meredith died because after having being attacked, threatened, and sexually assaulted, they had to silence her in some way, and you get that silence with death," he said.

Maresca said that after the long trial,all of the jurors doubts should have been removed.

"You must have certainties. Doubts belong to an earlier phase," he said.

If convicted of murder, Knox could face life in prison. She is simultaneously being tried in a civil suit in which prosecutors are asking for $12 million in damages for the Kercher family.

In addition, she is being tried for slander because in an odd confession during an all night interrogation she told police she had a vision of being at the crime scene that night and that a bar owner, Patrick Lumumba, was also present.

Lumumba was arrested, but later cleared. He has sued Knox for defamation. Conviction on that charge could result in a six year prison sentence.

Knox has since retracted the statement and said it was made under duress while police were treating her aggressively and even hit her on the back of her head.

ABC News' Nikki Battiste contributed to this report