A Florence court has upheld a slander conviction against Amanda Knox for wrongly accusing a bar owner of murdering the British student Meredith Kercher.

The American, 36, had asked for the conviction to be dropped, saying she had returned to Italy in the hope of “clearing my name once and for all of the false charges against me”.

She cried when the sentence was read on Wednesday and told her lawyers: “I didn’t expect it, I’m very disappointed,” the Italian news agency Ansa reported.

Knox had earlier told the judge: “I never wanted to slander Patrick [Lumumba, the bar owner]; he was my friend.”

Her lawyer, Carlo Dalla Vedova, told journalists outside court he was surprised by the court’s decision and did not rule out launching an appeal against the verdict.

Knox arrived at the appeal court with her husband, Christopher Robinson, but did not respond to questions from journalists before the closed-door hearing.

Knox, who along with her Italian ex-boyfriend Raffaele Sollecito spent four years in prison after being convicted over Kercher’s murder in 2007, had asked for the slander conviction to be dropped on the basis of a ruling by the European court of human rights in 2019 that found her defence rights had been violated during police questioning in 2007. Italy’s top court ordered a retrial of the slander conviction in October.

The challenge to the conviction was also enabled by a 2022 change to Italy’s code of criminal procedure.

Kercher, a 21-year-old student from Coulsdon, south London, was murdered in the home she shared with Knox in the university town of Perugia in November 2007. Her body was found in her bedroom, partly undressed with multiple stab wounds. She had been sexually assaulted.

Knox was handed a three-year jail term after wrongly accusing Lumumba, who owned a bar where she worked part-time in Perugia, of having committed the crime. Lumumba spent two weeks in jail and was released only after a witness came forward with an alibi for him. Knox’s sentence was served during the four years she was imprisoned before being found not guilty of Kercher’s murder on appeal in 2011.

Lawyers for Knox, who at the time was a 20-year-old student who spoke basic Italian, argued she made the allegation against Lumumba under police duress and did not have legal assistance or an interpreter.

On Wednesday she reportedly told the judge that Lumumba “took care of me and consoled me for the loss of my friend”. She added: “I’m sorry I wasn’t able to resist the pressure and that he suffered. I humbly ask you to declare me innocent.”

During the hours of police questioning she was a “scared and deceived” 20-year-old, she said. “I couldn’t be the witness they wanted against Patrick. I didn’t know who the murderer was. I was exhausted, confused and forced to submit.”

Lumumba did not attend the hearing but his lawyer, Carlo Pacelli, said he was “very happy” that the sentence had been upheld. “She tried to play the victim here but in the end the court convicted her,” Pacelli told the Guardian. “Patrick went to prison because Amanda was in prison.”

Pacelli said Lumumba received none of the compensation money that Knox was ordered to pay over the allegation, which led him to lose his business and move his family out of Italy.

Knox and Sollecito were definitively acquitted of Kercher’s murder in a high court ruling in 2015 that described “stunning flaws” in the investigation that led to their convictions.

Rudy Guede, who was the only person definitively convicted of the murder, was released from prison in November 2021 after completing 13 years of a 16-year-sentence.