Was there another person Bruno had problems with? What caused those conflicts, and how did they resolve it?

Bruno had problems with Lt. Kotler. He didn't trust him around his mother but couldn't figure out why.... it was simply a feeling of discomfort. Later, Bruno stands back and allows Shmuel to be beaten, rather than explain what happened. Once, again, he was afraid of Kotler. Bruno also questions Kotler's rellationship with his sister. All of these feeling are based upon mistrust that a young boy can instinctively feel but find incomprehensible.

This coflict is not resolved until Lt. Kotler is transferred from the camp.