Amanda Knox's retrial for the 2007 murder of her British roommate Meredith Kercher began on Sept. 30.

Knox was convicted in 2009 of killing Kercher, a 21-year-old British exchange student who was found stabbed to death, according to CNN. The conviction against Knox and her boyfriend at the time, Raffaele Sollecito, was overturned in 2011 for "lack of evidence."

Knox, 26, told the TODAY show one Sept. 20 she would not be returning to Italy for the trial.

"I was already imprisoned as an innocent person in Italy, and I can't reconcile the choice to go back with that experience," Knox said. "It's not a possibility, as I was imprisoned as an innocent person and I just can't relive that."

"I don't think I'm going to be put back in prison. I think that we're going to win. That's why I'm fighting this fight, that's why I continue to put forth the defensive argument in court."

In 2012, Italy's Supreme Court ruled that the acquittal is overturned and the case against Knox be tried. During the original trial, Knox's crime was portrayed as a "twisted sex game gone wrong," CNN reports.

Knox's defense lawyer Giulia Bongiorno told the court on Monday there is lack of DNA evidence placing Knox at the murder scene, Reuters reports. However, there is plenty of DNA on Rudy Guede, the only person in jail for the crime.

"How is it possible to find enormous quantities of traces of Guede and not a trace of Amanda," Bongiorno asked the court.

Bongiorno added the only "trace of Sollecito was on Kercher's bra clasp, which the defence say was due to contamination," according to Reuters.

Knox told the TODAY show she was unsure that the United States would allow her to be extradited if the Italian courts re-convict her, and her lawyers have not looked into the matter.

"That's not the primary concern of my lawyers right now,'' she said. "I don't believe that they have, precisely because they're still confident that we can win this."