PERUGIA, Italy (AP) — Amanda Knox left prison Monday, a free woman for the first time in four years, after an Italian appeals court threw out the young American’s murder conviction for the brutal stabbing death of her British roommate after a drug-fueled sexual assault.

Knox, 24, collapsed in tears after the verdict was read, a stunning reversal in a sensational saga that became a cause celebre in the U.S. Her co-defendant and former boyfriend, Italian Raffaele Sollecito, also was cleared of killing 21-year-old Meredith Kercher in 2007.

“We’re thankful that Amanda’s nightmare is over,” her younger sister, Deanna Knox, told reporters outside the courthouse. “She suffered for four years for a crime she did not commit.”

About 90 minutes after the verdict was handed down, a black Mercedes carrying Knox was seen leaving the prison. She was expected to board a commercial flight for home on Tuesday.

The fatal blow to the prosecution’s case was a court-ordered DNA review that discredited crucial genetic evidence used to convict Knox and Sollecito in 2009. They were sentenced to 26 and 25 years, respectively.

While waves of relief swept through the defendants’ benches in the courtroom, members of the Kercher family, who flew in for the verdict, appeared dazed and perplexed.