FLORENCE, Italy (AP) — An Italian prosecutor on Tuesday demanded that an appellate court find Amanda Knox guilty of the 2007 murder of her British roommate, a killing he argued may have been rooted in arguments about cleanliness and triggered by a toilet left unflushed by the only man now in jail for the murder.

Prosecutor Alessandro Crini called for 26-year sentences for Knox and Raffaele Sollecito, her co-defendant and former boyfriend, following more than 10 hours of closing arguments over two days. Knox and Sollecito deny any involvement in the killing.

Crini departed from past scenarios by suggesting the crime was not so much sexually fueled — an erotic game that got out of control, as the lower court prosecutor described it — but an act of physical violence with a sexual expression.

He alleged that Knox and Sollecito acted with another man in an explosion of violence sparked by tension between Knox and British student Meredith Kercher.

Crini argued that Rudy Guede — a native of Ivory Coast now serving a 16-year sentence for the murder — may have inflamed tensions between Knox and Kercher after he defecated in a toilet inside the women's apartment and didn't flush.

Crini said Guede, who was friendly with young men living in a neighboring apartment, had done the same thing the previous week. "It is an absolutely disgusting and incongruous habit that he evidently had," Crini said.

Testimony in previous trials had cited tensions between Kercher and Knox over the cleanliness of the house they shared with two Italian roommates.

Kercher's murder in the idyllic hillside town of Perugia is getting its third trial after Italy's highest court annulled an appellate ruling overturning the 2009 guilty verdicts against Knox and Sollecito. They were convicted in the first trial, and sentenced to 26 years and 25 years, respectively. Knox's sentence included 1 year for slander.

Knox's lawyer, Carlo Dalla Vedova, said the shift in the prosecution's theory about events leading up to the killing "confirms the lack of proof."

"In a trial based on clues, all the facts can be interpreted. This prosecutor worked very hard, but it doesn't change the situation. There are too many doubts. It calls for only an acquittal," Dalla Vedova said.

Kercher's body was found in a pool of blood in her locked bedroom on Nov. 2, 2007. Her throat was slit and there were signs of sexual aggression.

Kercher was stripped naked during the attack, and prosecutors allege that her bra was removed with a knife that tore off a clasp, one of the most-disputed pieces of evidence in the case. Guede was convicted in the murder on evidence that included physical evidence from a vaginal swab of the victim.

Crini also urged that Knox's separate sentence for slander for falsely blaming Kercher's murder on a Congolese-born bar owner, Diya "Patrick" Lumumba , be raised from three years to four years because, Crini argued, she lied to deflect suspicion from herself — which would be an aggravating circumstance.

Knox returned to the United States a free woman in 2011 after the appellate court ruling, having spent four years in jail, and has remained there for this trial. Sollecito, who also is free, had attended two hearings but was not in court on Tuesday.

In a statement released in Seattle, Knox said her lawyers had filed an appeal of the slander conviction — the only part of the case confirmed by Italy's highest court — with the European Court of Human Rights in Strasbourg, France, claiming the accusation against Lumumba was coerced by police who failed to inform her she was a suspect in Kercher's murder.

"The police were the ones who first brought forth Patrick's name saying they knew I was going to meet him the night of Meredith Kercher's murder, which was not true," Knox said. "I have stated many times that my original comments about Patrick were coerced by the police and not true."

Lumumba's lawyer, Carlo Pacelli, disputed that in his summing up on Tuesday, saying that Knox named Lumumba "spontaneously."

"Amanda had a double personality," Pacelli said. One the one hand she was "good, compassionate, tender," and on the other "a female Lucifer, diabolical, satanic."

Crini also challenged new interpretations of genetic evidence cited by a Perugia appeals court when it overturned the guilty verdicts. He said a DNA sample on the blade of the presumed murder weapon was clean and belonged to Kercher.

That finding, which was key to the convictions, was cast in doubt during the appeals trial. All of the evidence is up for re-examination after the high-court blasted the appellate court's reasoning.

The trial continues Dec. 16 with closing arguments by the Kercher family lawyer, Francesco Maresca, followed by Knox's defense team the next day. A verdict could come in January.

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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>