An Italian court has reconvicted American Amanda Knox of slander and handed her a three-year jail sentence.

The verdict was related to the 2007 murder of 21-year-old British student Meredith Kercher, a case during which Knox falsely implicated local barman Patrick Lumumba.

Knox will not serve any further jail time despite Wednesday's sentence, as she spent four years in prison in Italy after her own initial conviction in Kercher's murder trial.

She and then-boyfriend Raffaele Sollecito were initially convicted over the killing in a 2009 trial, which was overturned in 2011. Knox then returned to the US, but she was found guilty again in a 2014 retrial before finally being cleared by Italy's highest court in 2015.

Judges have now upheld her separate 2009 conviction for slander against Lumumba.

Knox is set to appeal against the verdict to Italy's highest court.

What was the reaction?

Knox was in tears as the judges delivered the verdict.

"I didn't expect this. I am very disappointed," said the 36-year-old, who had returned to Italy for the trial.

Knox implicated Lumumba in Kercher's stabbing during a police interrogation following her arrest over the murder in late 2007.

She claimed that the Italian police threatened her with 30 years in prison and used violence to pressure her to name the Congolese barman as the killer. 

"Amanda is very upset ... from the outcome of this hearing, she was looking to have a final point of all this, 17 years now, judicial procedure," lawyer Carlo Dalla Vedova said.

Lumumba spent two weeks in prison in 2007 after Knox's allegation before being freed without charge. His lawyer Carlo Pacelli told reporters before the hearing that the slander conviction should be upheld.

"When Patrick was accused by Amanda, he became known everywhere as the monster of Perugia," he said.

Who is Amanda Knox?

Knox was a 20-year-old exchange student in Perugia when her British roommate, Kercher, was found dead in her bedroom on November 2, 2007. 

Suspicion fell on Knox and Sollecito, with whom she had been involved for just about a week. Both were convicted in 2009, before ultimately being exonerated six years later.

Ivorian Rudy Guede was convicted of Kercher's murder in October 2008 after his DNA was found at the scene and sentenced to 16 years in jail. He was granted early release in 2021.

km/nm (AP/DPA)