michelle kazinski has the details. >> reporter: if amanda knox looked tired or upset coming into courtmelted into smiles. seeing her supporters. for the first time in more than three years, since her roommate was found murdered in their hillside apartment, the court is tackling the case with fresh eyes. leaving amanda and her family guardedly elated. >> we have said if the bits of evidence are re-examinere-exami the truth will be found out. >> reporter: evidence that was found on the knife that the prosecutors claim was the murder weapon and on the victim's bra. they will retest it. they may even dismantle the knife in case other evidence is hiding. the defense believes it is not the murder weapon. it was found in a kitchen drawer. the boyfriend was also convicted of sexual assault and murder and this is his appeal too. a trace of his dna was on meredith's bra clasp but nowhere else on it or the scene. his experts don't even think it is his dna at all. >> no match. no match. i did a deep exam nation of the results obtained by the police and i am sure to exclusion. >> reporter: could ne