FLORENCE, Italy -- FLORENCE, Italy (AP) — A court-appointed expert testifying in U.S. student Amanda Knox's third murder trial in Italy said Wednesday that a new trace of DNA found on the handle of the knife alleged to have been the murder weapon belongs to Knox and not the victim.

That testimony bolsters the defense, which claims the kitchen knife was not the weapon used in the bloody 2007 slaying of Knox's British roommate, 21-year-old Meredith Kercher.

As things stand, there's no confirmed DNA belonging to Kercher on the knife; one piece of DNA on its blade that was first attributed to Kercher has been disputed on appeal.

Expert Andrea Berti testified Wednesday that the minute new DNA trace from the knife's handle showed "considerable affinity" with Knox's DNA, while not matching that of Kercher. It also did not match the DNA of Knox's co-defendant Raffaele Sollecito or Rudy Guede, an Ivorian man who has been convicted separately in the brutal slaying.

Knox defense lawyer Carlo Dalla Vedova told The Associated Press that the testimony confirms their contention that the knife was used solely for preparing food. "The report confirms that this is a kitchen knife. It is not a murder weapon," Dalla Vedova said.

Luca Maori, Sollecito's defense lawyer, said the trace's very existence also indicated the knife had not been washed. "It is something very important," he said. "It is absurd to use it for a murder and put it back in the drawer."

The DNA evidence on the knife found in a drawer at Sollecito's place has been among the most hotly contested pieces of evidence in the original trial and now in two appeals.

Knox and Sollecito were convicted in 2009 of murdering Kercher, and sentenced to 26 and 25 years in jail, respectively. The conviction was overturned on appeal in 2011, freeing Knox to return to the United States where she remains for the latest appeal.

Prosecutors have contended the knife was the murder weapon because it matched Kercher's wounds, and presented evidence in the first trial that it contained Kercher's DNA on the blade and Knox's on the handle.

However, a court-ordered review during the first appeal in Perugia, where the murder happened, discredited the DNA evidence. It said there were glaring errors in evidence-collecting and that below-standard testing and possible contamination raised doubts over the DNA traces linked to Kercher on the blade, as well as Sollecito's DNA on Kercher's bra clasp.

Italy's highest court, however, ordered a fresh appeals trial, blasting the acquittal as full of contradictions and questioning failures to retest some of the DNA evidence in light of advanced new technology.

Sollecito addressed the court on Wednesday, as allowed by the Italian judicial system. He said he hadn't taken seriously enough the accusations at the beginning because he was too caught up with his new romance with Knox to grasp what was happening.

"Me and Amanda were living the dawn of a carefree romance and we wanted to be completely isolated in our love nest," Sollecito said.

He struggled with his composure as he pleaded with the court to acquit him. "I hope I'll have the chance to live a life, a life, because at the moment I don't have a real life," he said. "That's what I'm asking you."

The DNA trace is the last new piece of evidence to be entered in the latest trial. Prosecutors begin their summations later this month, followed by the defense in December. A verdict is expected in January.

Earlier on HuffPost:

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  • Nov. 2, 2007

    British student Meredith Kercher, 21, is <a href="http://www.huffingtonpost.com/huff-wires/20130326/eu-italy-knox-chronology/" target="_blank">found murdered</a> in the Perugia, Italy apartment she shares with 20-year-old Amanda Knox, an American student. Post-mortem examination reveals evidence of sexual activity before death. <em>This undated file photo released on Nov. 3, 2007 by the Italian Police shows 21-year-old murdered British university student Meredith Kercher. (AP Photo/Italian Police, ho, file)</em>

  • Nov 6, 2007

    Knox and 23-year-old boyfriend Raffaele Sollecito (right) <a href="http://www.huffingtonpost.com/huff-wires/20130326/eu-italy-knox-chronology/" target="_blank">are arrested</a>. Knox's boss, 38-year-old bar owner Patrick Lumumba, is also arrested after revealing he'd canceled Knox's shift the night Kercher is murdered. <em>This photo taken Friday Nov. 2, 2007, and made available on Thursday Nov. 8, 2007 shows Amanda Marie Knox, left, and Raffaele Sollecito, looking on outside the rented house where 21-year-old British student Meredith Kercher was found dead, in Perugia, Italy. (AP Photo/Stefano Medici, File)</em>

  • Nov. 20, 2007

    Lumumba is <a href="http://www.huffingtonpost.com/huff-wires/20130326/eu-italy-knox-chronology/" target="_blank">released from jail</a> for lack of evidence after Knox implicates him to police. <em>Congolese Patrick Lumumba Diya (R) with his lawyer Carlo Pacelli leaves the police headquaters in Perugia, 20 November 2007. (STR/AFP/Getty Images)</em>

  • Dec. 6, 2007

    20-year-old drug dealer and Ivory Coast national <a href="http://www.huffingtonpost.com/huff-wires/20130326/eu-italy-knox-chronology/" target="_blank">Rudy Hermann Guede</a> becomes a third suspect. He is extradited from Germany and taken into custody upon his arriving in Italy. <em>Ivory Coast citizen Rudy Hermann Guede arrives at Rome's Fiumicino airport, 06 December 2007 after being extradited from Germany where he was arrested last 20 November. (TIZIANA FABI/AFP/Getty Images)</em>

  • Oct. 28, 2008

    Judge indicts Knox and Sollecito on murder and sexual assault charges. Guede, who was granted a fast-track trial, is convicted of murder and sexual assault and sentenced to 30 years in prison after confessing to being in the house on the night of the murder. He maintains his innocence, instead blaming an Italian stranger for the crime. <em>Rudy Hermann Guede, of the Ivory Coast, center, is escorted by penitentiary police officers as he arrives at the opening of his appeal's trial in a Perugia court, central Italy, Wednesday, Nov. 18, 2009. (AP Photo/Stefano Medici)</em>

  • Sept. 26, 2008

    Knox and Sollecito meet in court for the first time since their arrests. <em>In this Sept. 26, 2008 file photo, American murder suspect Amanda Knox , center, is escorted by Italian penitentiary police officers to Perugia's court at the end of a hearing, central Italy. (AP Photo/Pier Paolo Cito, files)</em>

  • Jan. 16, 2009

    Knox and Sollecito's trial begins in Perugia. <em>Amanda Knox smiles to her lawyer Luciano Ghirga as she arrives at Perugia's court, Italy, Friday, Jan. 16, 2009. (AP Photo/Alessandra Tarantino)</em>

  • March 6, 2009

    After claiming she was pressured to name a suspect, Knox tells the court she was at Sollecito's house when Kercher's murder took place. <em>American murder suspect Amanda Knox, center, is escorted by Italian penitentiary police officers from Perugia's court after a hearing, central Italy, Tuesday Sept. 16, 2008. (AP Photo/Antonio Calanni)</em>

  • June 12, 2009

    Knox <a href="http://www.huffingtonpost.com/huff-wires/20130326/eu-italy-knox-chronology/" target="_blank">takes the stand</a>, telling the court she was shocked by Kercher's death. She offers the alibi that she spent that night at her boyfriend's house and accuses police of beating her into making false statement. <em>Amanda Knox, accused of killing her British housemate two-years ago, takes place in the courtroom on June 12, 2009 in Peruggia. (TIZIANA FABI/AFP/Getty Images)</em>

  • Nov. 21, 2009

    Italian prosecutors request life sentences for both Knox and Sollecito. <em>U.S. murder suspect Amanda Knox reacts during a hearing at Perugia's court, Italy, Saturday, Nov. 21, 2009. (AP Photo/Alessandra Tarantino)</em>

  • Dec. 4, 2009

    Jury retires to consider verdicts. Both defendants are found guilty. Knox is sentenced to 26 years in prison, while Sollecito receives 25 years. <em>U.S. murder suspect Amanda Knox is accompanied to a penitentiary police van as she leaves the court after a final hearing before the verdict, in Perugia, Italy, Friday, Dec. 4, 2009. (AP Photo/Pier Paolo Cito)</em>

  • Dec. 22, 2009

    Guede's <a href="http://www.huffingtonpost.com/huff-wires/20130326/eu-italy-knox-chronology/" target="_blank">conviction is upheld</a> by appeals court, though his sentence is cut to 16 years. <em>In this Dec. 22, 2009, file photo, Rudy Hermann Guede of Ivory Coast, looks on during his appeals trial in Perugia, Italy. (AP Photo/Stefano Medici)</em>

  • June 1, 2010

    Knox is indicted on slander charges for claiming she was beaten by police when questioned in 2007 about her roommate's slaying. <em>Jailed U.S. student Amanda Knox, right, is escorted by police as she arrives for a preliminary hearing in Perugia, Italy, Tuesday, June 1, 2010. (AP Photo/Fabrizio Troccoli)</em>

  • Nov. 24, 2010

    Knox and Sollecito's <a href="http://www.huffingtonpost.com/huff-wires/20130326/eu-italy-knox-chronology/" target="_blank">appeals trial begins</a> in Perugia. <em>U.S. murder suspect Amanda Knox, right, is escorted by a penitentiary guard, prior to the start of a hearing in her appeals trial in the murder of her British roommate Meredith Kercher, in Perugia's courthouse, Italy, Wednesday, Nov. 24, 2010. (AP Photo/Gregorio Borgia)</em>

  • Dec. 16. 2010

    Guede's conviction and 16-year prison sentence <a href="http://www.huffingtonpost.com/huff-wires/20130326/eu-italy-knox-chronology/" target="_blank">are upheld</a> by Italy's highest criminal court. <em>One of the three suspects in the murder of British student Meredith Kercher, Rudy Guede from the Ivory Coast (C), of the United States, leaves at a court hearing in Perugia on September 27, 2008. (TIZIANA FABI/AFP/Getty Images)</em>

  • June 29, 2011

    The appeals court orders an independent forensic report, which <a href="http://www.huffingtonpost.com/huff-wires/20130326/eu-italy-knox-chronology/" target="_blank">questions much of the DNA evidence</a> used in convicting Knox and Sollecito. <em>Amanda Knox (L) looks Raffaele Sollecito (R) as she arrives in Perugia's court of Appeal during the hearing of her appeal against her murder conviction on June 27, 2011 in Perugia, Italy. (Photo by Franco Origlia/Getty Images)</em>

  • Oct. 3, 2011

    The appeals court <a href="http://www.huffingtonpost.com/huff-wires/20130326/eu-italy-knox-chronology/" target="_blank">overturns the murder convictions</a> of Knox and Sollecito and orders their immediate release. <em>Amanda Knox breaks down in tears after hearing the verdict that overturns her conviction and acquits her of murdering her British roommate Meredith Kercher, at the Perugia court on October 3, 2011 in Perugia, Italy. (Photo by Pier Paolo Cito - Pool/Getty Images)</em>

  • March 26, 2013

    Italy's highest criminal court <a href="http://www.huffingtonpost.com/huff-wires/20130326/eu-italy-knox-chronology/" target="_blank">orders a new trial</a> after overturning the previous acquittal of Knox and Sollecito. <em>Luciano Ghirga, lawyer of Amanda Knox, center, talks to journalists as he leaves Italy's Court of Cassation, in Rome, Tuesday, March 26, 2013. (AP Photo/Gregorio Borgia)</em>