They found her DNA in her own apartment, imagine that? I haven't been following the case, but a former colleague (a first generation Italian/American) has been, and I know he thought the prosecution had a weak case, and a flimsy case by American standards. Maybe she did it, maybe she didn't, but "beyond a reasonable doubt" probably wasn't met, FWIW.
Since Italy's laws are based on Roman Law, not Anglo Saxon Law, I believe that there is a presumption of guilt.