American college student Amanda Knox boarded an airplane in Italy, heading to the United States yesterday, after a jury overturned her murder conviction, Voice of America said. Knox collapsed in tears while the courtroom erupted Monday evening, when the court decision was read. Her former Italian boyfriend and co-defendant, Raffaele Sollecito, also was exonerated and freed from prison. Knox was appealing her 26-year prison sentence on charges of murdering her roommate, Meredith Kercher, in 2007. Court-appointed independent forensic experts said the DNA used to convict Knox was unreliable and possibly contaminated by police.