Amen. (2002)

Kurt Gerstein—a member of the Institute for Hygiene of the Waffen-SS—is horrified by what he sees in the death camps. he is then shocked to learn that the process he used to purify water for his troops by using Zyklon-B, is now used to kill people in gas chambers.

Directed by: Costa-Gavras

Starring: Ulrich Tukur, Mathieu Kassovitz, Ulrich Mühe, Michel Duchaussoy, Marcel Iureș, Ion Caramitru

Links: IMDb, Movie posters, Movie stills