Conversation so far:
What did Aleksandr Solzhenitsyn do in World War II?
During the war, Aleksandr Solzhenitsyn served as the commander of a sound-ranging battery in the Red Army, was involved in major action at the front, and was twice decorated.
What else happened while Aleksandr Solzhenitsyn was in World War II?
While serving as an artillery officer in East Prussia, Aleksandr Solzhenitsyn witnessed war crimes against local German civilians by Soviet military personnel.

Question: What type of crimes did he see?
Self-contained rewrite: What type of crimes did Aleksandr Solzhenitsyn see Soviet military personnal commit against local German civilians?