The former US exchange student also said she was staying away from the trial out of fear of being wrongly convicted.
"I didn't kill. I didn't rape. I didn't rob. I didn't plot. I didn't instigate. I didn't kill Meredith," Knox wrote.
Presiding Judge Alessandro Nencini read the five-page email written in Italian into the court record. He noted that the email, presented by Knox's lawyers before their closing arguments, was not a normal procedure in Italy.
"Who wants to speak at a trial, comes to the trial," Nencini said, adding that he had to take the word of her lawyers that the email originated with Knox. "I never saw her, I don't know her."
More From This Section
Knox explained her absence was out of fear that she would be wrongly convicted, which she contends happened during the first trial against her and her former boyfriend, Italian Raffaele Sollecito. The case against Knox and Sollecito is being heard for a third time.
"I am not in court because I am afraid. I am afraid that the vehemence of the prosecution will make an impression on you, that their smoke will get in your eyes and blind you," Knox said in the email.
She said she was following the case closely "given that my life is at stake."
Meredith Kercher, 21, was murdered in November 2007 in the apartment she shared with Knox in the picturesque Italian university town of Perugia. She had been raped, stabbed dozens of times in the face, had her throat slashed and her body left beneath a blanket in her bedroom.