Amanda Knox, the American accused of killing her British flatmate Meredith Kercher, has said she will become a fugitive from justice if an Italian court decides to uphold her murder conviction later this month.

Knox, 26, is facing the possible reinstatement of a hefty sentence for her alleged part in the death of the 21-year-old Leeds University student in Perugia in 2007. She and her co-defendant, Raffaele Sollecito, are in the final stretches of a second appeal against convictions handed down in 2009.

On Thursday the 29-year-old Italian sat in court as his defence lawyer argued that he was the innocent victim of a deeply flawed prosecution and should be allowed to walk free.

But the Seattle-based student, as is her right under Italian law, has not returned to Italy for the new proceedings at the Florence appeals court, saying she fears being found guilty and sent back to jail.

In an interview on Thursday, she appeared to confirm that she has no intention of returning to Italy if the verdict goes against her. Asked by the daily newspaper La Repubblica what she would do if her conviction were upheld, she was quoted as saying: "In that case I will be – how do you put it? – a fugitive."

If the court, which is expected to rule on 30 January, upholds the guilty verdicts its judgment will still have to be validated by Italy's supreme court. If that happens, Italy could request Knox's extradition from the US, a move her lawyers would challenge, at least in part on the US legal principle of double jeopardy – the premise that someone cannot be tried for a crime of which they have been acquitted.

Legal experts, however, say the picture is by no means clear cut as the 2011 appeal verdict that quashed Knox and Sollecito's convictions was not confirmed by the supreme court, which ruled last year that the decision to acquit was flawed.

On Thursday, Sollecito's defence lawyer Giulia Bongiorno wrapped up her argument for why he should again be cleared of the 2007 murder, insisting that police and prosecutors overlooked signs of his innocence because they were keen to avoid public fright over "a monster" on the loose. "For some investigators, the first suspects are like first loves: never forgotten," she said, Reuters reported. Both defendants insist they are innocent.

In her interview Knox said that although she was reasonably optimistic about the verdict, she was also approaching it with trepidation as "every time that I've thought my innocence would be acknowledged I have been convicted".

She said she badly wanted to talk directly to Kercher's family, but was aware that such a move would not be welcome.

"I still want to talk with them, tell them directly that I had nothing to do with Meredith's death, that I cared about her and that we were friends," she was quoted as saying. "But I know that they see me as their daughter's murderer [and] are convinced that it was me who killed her, and so it is still not the moment to speak with them. But that day will come."

The comments were not welcomed by Francesco Maresca, the Kercher family's lawyer, who told the Ansa news agency: "Amanda must act like a defendant … she should stop making these statements."

Another man, Rudy Guede, from Ivory Coast, is serving a 16-year sentence, cut from 30 years on appeal, for Kercher's killing. But tThe Italian supreme court, in the reasoning for its decision last year, said the Florence court should re-examine the possibility that Guede did not act alone.