The Seattle native and former University of Washington student celebrated her second birthday in jail last Thursday in a Perugia, Italy. She is 22.
In an exclusive interview with Amanda's sisters, 14-year-old Ashley, and 20-year-old Deanna Knox, said on "The Early Show" Tuesday, Amanda was hoping that she wouldn't spend another birthday in jail, but she made the most of the celebration.
"She always finds a way to be happy. She was still smiling," Deanna said.
According to Knox's sisters, Amanda made a cake for her family because she couldn't have one brought to her by her family from outside the jail.
"We sang her happy birthday as she walked in and ate cake with her," Deanna said. "It was only one hour, but we got to spend her birthday with her."
Knox received presents from her family, but only the ones that were sent to her, Deanna said, because the family can't bring gifts directly to the jail.
The sisters described to "Early Show" co-anchor Julie Chen their last visit to the jail on Tuesday. Deanna said Amanda described herself as "tranquil" during their visit.
"The only sad part," Deanna said, "was the fact that we had to say goodbye."
The sisters are returning home Thursday, while there is a two-month summer recess in Knox's murder trial.
Amanda has been on trial since January, along with her former Italian boyfriend Raffaele Sollectio. The two are charged with sexually assaulting and murdering Knox's 21-year-old British roommate, Meredith Kercher.
Amanda has maintained her innocence throughout the trial.
Last week, she seemed to catch a break in her defense when a coroner testified that the knife believed to be the murder weapon is not compatible with the victim's stab wound. He also testified that there is no evidence that Kercher was assaulted by more than one person.
Rudy Hermann Guede, an Ivory Coast national, who had also denied wrongdoing, was convicted last year and sentenced to 30 years in prison for the murder and sexual assault of Kercher.
Amanda's hearings will be held Friday and Saturday. Her trial will then resume this fall.
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