Alessandro Crini also called for a 26-year sentence for Knox's former boyfriend, Raffaele Sollecito, while speaking at an appeals court in Florence where the retrial has been taking place since September 30.
Both Knox and Sollecito were convicted for Kercher's murder in 2009, but their convictions were overturned in 2011 over a "lack of evidence." Last year, the Italian Supreme Court decided to retry the case claiming the jury that acquitted them did not consider all the evidence.
The court said it still needed answers from several discrepancies in the testimony from the trial that acquitted the suspects.
In his second day of closing arguments, Crini recapped the evidence against both Knox and Sollecito highlighting Knox's strange behavior -- kissing Sollecito outside of the crime scene, doing cart wheels and yoga poses while waiting to be interrogated at the police station -- and asked for 26-year jail sentences for both. He also asked for an additional four years to be added to Knox's sentence for slander.
That charge is related to Patrick Lumumba, a former employer of Knox's who spent several weeks in jail after she falsely accused him of Kercher's murder. While she later claimed that she only named him after being interrogated for hours without water or sleep, Lumumba won a defamation suit against the Seattle native.
Both suspects have maintained their innocence throughout the retrial.
Knox, who returned home to Seattle after her acquittal, has not been in court for the retrial. If found guilty, is it unlikely that the U.S. would extradite Knox given the country's double jeopardy laws, which prevent suspects from being tried twice for the same crime.
A third man, Rudy Guede, was also convicted for the slaying of Kercher in a separate proceeding and was sentenced to 16 years in prison.