Complex sentence: The family's massacre by an execution squad, consisting of German soldiers overseen by Donatti, is secretly witnessed by Vittorio, who can hardly believe the horror-father, mother, brothers, wives, children-all murdered in front of his eyes.
Split into simpler sentences: The family's massacre by an execution squad, consisting of German soldiers overseen by Donatti, is secretly witnessed by Vittorio, who can hardly believe the horror. Father, mother, brothers, wives, children-all murdered in front of his eyes.