PERUGIA, Italy (AP) — The appeals case of Amanda Knox, the American student convicted of killing her British roommate, resumed yesterday with lawyers questioning independent experts who cast doubt on the evidence used in the first trial.

The 24-year-old from Seattle who has been behind bars since the November 2007 murder was in the Perugia courtroom, as was her co-defendant and onetime boyfriend, Raffaele Sollecito.

Ahead of the hearing, the first after the summer break, the sister of victim Meredith Kercher issued a letter asking the appeals court to assess “every single (piece) of evidence” so that justice can be done.

“My sister, a daughter brutally and selfishly taken from us nearing 4 years ago — and yet a not a single day goes by that we can grasp any peace or closure,” Stephanie Kercher wrote.

The appeals trial picked up where it left off before the summer recess in late July: with questioning of independent experts who have reviewed the collection and analysis of DNA evidence used to convict Knox and Sollecito.

The two were convicted in Dec. 2009 of sexually assaulting and killing Kercher in the apartment Knox and the 21-year-old Briton shared while studying in Perugia.

Both deny wrongdoing, and have appealed.