As the United States deports a former Nazi concentration camp guard to Germany, the world has been reminded again of the popular image of the Holocaust as one of impersonal mass slaughter. In the death camps, Jews and other victims died at the hands of murderers who didn’t know their victims but were filled with anti-Semitic hate.

But by the time that the death camps’ gas chambers became operational, approximately half of the Jews who would perish in the Holocaust were already dead. Many of these Jews were tortured or killed by “ordinary” non-Jews at close quarters: in apartments, in streets, in the woods and anywhere else Jews could be found. The perpetrators often knew or knew of their victims, and the means were often primitive: guns, axes, crowbars, bricks, fire, beating and drowning.

Jews did not face this kind of personalized anti-Semitic violence in every community. Our recently published book, “Intimate Violence: Anti-Jewish Pogroms on the Eve of the Holocaust,” identifies the factors that put Jews at risk in some places but not others. And these factors involve more than just anti-Semitism.