PERUGIA, Italy - American student Amanda Knox made a tearful plea on Monday to be acquitted of murdering her British roommate during a brutal erotic game, saying she was paying with her life for a crime she did not commit."I lost a friend, in the most brutal and inexplicable way possible. My absolute faith in the police authorities was betrayed, I've had to face absolutely unfair ... and baseless accusations. I am paying with my life for things I did not commit," said Knox, visibly shaking and fighting to hold back tears. Knox barely spoke Italian when she was arrested but addressed the court fluently.The Seattle native and her Italian boyfriend at the time, Raffaele Sollecito, are fighting a 2009 verdict that found them guilty of stabbing Leeds University exchange student Meredith Kercher to death during a brutal, drug-fuelled sexual assault.The panel of two professional and six lay judges retired to consider a verdict immediately after Knox's final plea. Their decision is expected late on Monday.Expectations are high among many in the United States that 24-year-old Knox will walk free from the Perugia prison where she has spent nearly four years, after a forensic review cast deep doubt on DNA evidence used to convict her and Sollecito.The appeal trial has gripped attention on both sides of the Atlantic, four years after 21-year-old Kercher's body was found in a pool of blood in the university town.Knox and Sollecito were arrested days after the murder, but have steadfastly maintained their innocence throughout. A third man, Ivorian drug dealer Rudy Guede, was imprisoned for his role in the murder.Prosecutors say Kercher was pinned down and stabbed to death when she resisted attempts by the three to involve her in an orgy. They say Knox was a cold-blooded, sex-obsessed girl who led her boyfriend astray.They have also pointed to a fraught relationship between the two women, saying the British exchange student resented her American roommate's promiscuity.The prosecution says plenty of other evidence links Knox to the crime, including her false accusation against a Congolese barman and a theft she and Sollecito are alleged to have staged in the apartment to throw police off track.