"It really appears [the judge] wants to get to the truth. And the truth is really going to set her free," Curt Knox told ABC News.
In 2009 Knox was sentenced to 26 years and her former boyfriend Raffaele Sollecito to 25 years for the stabbing of British student Meredith Kercher in their Perugia home in 2007.
The Seattle family is pinning its greatest hopes on a review of the DNA evidence that convicted Knox and Sollecito. The appeals panel is letting two independent Italian experts examine the forensics.
During the trial, Knox's lawyers argued that a sample of Kercher's DNA found on a kitchen knife was too weak to be tested and that a bra clasp with Sollecito's DNA had been contaminated. The defense doubts the knife was the murder weapon.
The defense team also scored a victory when a hearing discredited the testimony of Antonio Curatolo, a homeless drug addict who said he saw Knox and Sollecito on the night of the killing.