Scene 4 (Invention on a 6-Note Chord): Wozzeck goes back to the place where he killed Marie. Wozzeck thinks that the knife he killed Marie with will prove that he is the murderer. He throws the knife into the pond. When the blood-red moon appears again, he walks into the pond to try to wash the blood of his body, but he drowns. The Captain and the Doctor, passing by, hear Wozzeck moaning and rush off in fright.