After World War II, Pius XII charged Leiber and Bea with investigating the activities of Gertrud Luckner (later declared Righteous among the Nations), the pioneer of a German Catholic philo-Semitic and pro-Israel movement.Michael Phayer. 2009. The Catholic Church and the Holocaust, 1930–1965. Indianapolis: Indiana University Press, p. xvii, 57, 102, 166-167, 176, 199, 207, 221, 237, 239. The Holy Office in 1948 issued a monitum (or warning) to the group, due to concerns that the group's pro-Zionist activities were "encouraging religious indifferentism (the belief that one religion is as good as the next)". Leiber concluded in April 1950 there was nothing theologically wrong with the work of Luckner; Bea went further, actually affirming it.
