The verdict of Amanda Knox was announced in the Italian court on Monday, and the 24-year-old exchange student was acquitted of murder.
Free from the initial sentence of 26 years in prison, Knox is expected to return to Seattle on Tuesday with her family.
The verdict was delivered one-and-a-half hours after the promised 8 p.m. deadline, an indication that the jury did not have an easy time with the decision.
Knox was found guilty of slander for accusing bar owner Diya Patrick Lumumba of carrying out the crime. The judge set the sentence at three years, which she has already served, and ordered Knox to pay 22,000 euros.
Upon hearing the verdict reversal, Knox collapsed in tears, and wept uncontrollably as she was led back to prison by security guards to collect her belongings.
The Kercher family appeared dazed as the verdict was read by the judge after nearly 11 hours of deliberations by the eight-member jury.
Outside the court, hundreds of people gathered to watch the spectacle, many of them upset by the acquittal.
Knox and her Italian boyfriend Raffaele Sollecito were freed as the Italian appeals court overturned both of their guilty verdicts for murdering Knox's roommate Meredith Kercher in 2007.
Knox and Sollecito were convicted in 2009 after a ten month long trial, each sentenced to 26 and 25 years in prison.
Prosecutors had demanded that Knox's sentence be increased from 26 years to life, calling the murder of Kercher a senseless crime and Knox a she-devil as they portrayed her as a double-sided, sex-crazed party girl. Kercher's body was wounded over 40 times with her throat slit.
Kercher, 21, was stabbed to death in the apartment she shared with Knox. Prosecutors alleged the killing began like a sexual assault, while Knox and Sollecito said they spent the night at his house that night, watching a movie, smoking marijuana and having sex.
Knox had maintained her innocence throughout the trials, frequently casting questions to the authorities, why don't they believe me?
In Knox's final appeal on Monday, she gave an emotional speech.
I am not what they say I am. I did not kill. I did not rape. I did not steal, said Knox.
I didn't rape. I didn't steal. I was not there, Knox said as her voice trembled.
We had a good relationship. We were all available to each other. I shared my life, especially with Meredith. We had a friendship. We were friends. She was concerned for me. She was always kind to me. She cared about me.
We're thankful that the nightmare is over, Knox's sister Deanna Knox said. She has suffered for four years for a crime that she did not commit. We are thankful to the court for looking for the truth.
Knox was spotted leaving the Cappane prison at just after 5 p.m. EST in a Mercedes sedan with tinted windows, according to CNN.
A man identified as a friend of Knox's told CNN that her passport is valid (the passport was believed to have expired while she was in prison) and that Knox is expected to fly home to Seattle on Tuesday.
The U.S. State Department had earlier Monday offered a statement of support to Knox.
The United States appreciates the careful consideration of this matter within the Italian judicial system, said Victoria Nuland, a spokeswoman for the U.S.State Department. Our embassy in Rome will continue to provide appropriate consular assistance to Ms. Knox and her family.
The 24-year-old acquitted of murder said thats she was thankful to all those who shared my suffering and helped me survive with hope, Knox said in a letter.
Knox family members were spotted at Leonardo da Vinci airport in Rome saw Knox family members in a terminal. Knox was believed to have been escorted by police through a non-public entrance to the airport, according to CBS.
She just couldn't wait to get on the plane. She told me that, even though she wasn't yet on the plane, she felt like she was already flying. Knox's friend Giulia Alagna told The Early Show. Tuesday morning, Knox and Alagna spoke on the phone as the acquitted 24-year old waited for her flight.
She was just very, very happy to get on that flight, Alagna said.