According to Phayer, Leiber "sparked new life into Austrian bishop Alois Hudal's plan" to set up a "ratline" - an escape route from Europe for Nazis and fascists, including war criminals.
According to a history professor at the Pontifical Gregorian University, Leiber had no direct authority to correspond with Hudal but "[his] role as one of Pius XII's closest confidantes allowed the German Jesuit to act as the pope's intermediary and messenger."[REF]