After Bruno disappears, his father, the Commandant of Out-With (Auschwitz), commands his men to search for him, but they cannot find him. Bruno's mother and sister Gretel return to Berlin, thinking Brumo might have gone back there.
Bruno's father finds himself with a bad reputation among the Nazis because of the harsh way he treats his soldiers. He puzzles over what happened to Bruno until one day he finds a place where the barbed wire face separating the camp from the outside world is not secure. He realizes that Bruno probably got into the camp that way. From the pile of Bruno's clothes found near the spot, Bruno's father is able to conjecture that Bruno probably changed into the striped pajamas of the inmates and was mistaken for an inmate, then killed. This is, in fact, what happened: Bruno was herded with Shmuel into a gas chamber, and both boys were gassed.
As he realizes what must have happened, Bruno's father is grief stricken. He becomes depressed and no longer is concerned with his career. When he ends up disgraced and is taken off by his soldiers, he doesn't care.
Bruno's father thought he could keep his family safe from the horrors of Auschwitz but learned the hard way that what we do to others comes back to hurt us.