The federal court records read like variations on the same morality play sharing the same opening scene: A neighbor known as quiet and friendly is accused of Nazi war crimes, stunning residents of nearby bungalows or adjoining apartments.

"He was always out ready to help his neighbors," Kathy Blitch testified at the trial of Conrad Schellong, with whom she shared a back porch on Chicago's Northwest Side.

But Schellong, a retired machinist, was also among a number of concentration camp guards whose dark pasts caught up with them decades after they had bluffed their way into this country.

Many lived in Chicago, where the ethnic patchwork made it easy to blend in among various displaced people rebuilding their lives after World War II. Having participated in the horrors of Auschwitz and Treblinka, former Nazis and their collaborators went on to live in quiet anonymity in Cicero and Schiller Park, Brookfield and Brighton Park.