In US law there is such a thing as being an accessory to murder after the fact.
Its not accessory to murder. She would have to knowlingly and willingly dispose of Rudy Guede’s crime. But obstruction of an investigation or making false statements, probably. I believe her mistatements over Patrick Lumbumba could be considered for that, even if she barely understood the Italian language (they should have had an interpreter there, during their 10 pm to 6 pm 3rd world interrogation of her). In fact I believe she was convicted of making false statements and has not bothered to contest that because her time in prison cover time served for that lesser crime.