Vatican City is recognized,under international law,as a sovereign nation and one would think that the Pope is the Prime Minister,Justice Minister,etc.So could the Pope actually *expel* him from Vatican City,thus opening him up to possible extradition? Hmmm....
Extradition to where? Massachusetts? On what grounds? The guy may be a dirtbag, but the Commonwealth's Attorney found nothing with which to charge him. Stick him in a monastery, feed him bread and water. It's more than the secular authorities could do to him.