Sept. 16 (UPI) -- A letter from 1942 uncovered by a Vatican archivist shows that Pope Pius XII, who served as pontiff during World War II, likely knew about the Holocaust, an Italian newspaper reported Saturday.
The correspondence also indicates the late Pope, who has long been criticized for failing to call out crimes against humanity committed by the German Nazis, was likely aware of the homicidal nature of the regime's concentration camps, according to the Rome daily Corriere della Sera.
The newspaper said the Dec. 14, 1942, letter, which was uncovered by Vatican archivist Giovanni Coco, is a correspondence between the anti-Nazi German Jesuit priest Lothar Konig and Pius' secretary, Robert Leiber.
In an interview, Coco said the correspondence referred to a "blast furnace" at the Belzac concentration camp and said the priest states that "up to 6,000 men die every day, mainly Poles and Jews."
The new correspondence, if authenticated, would cast serious doubt on previous claims that Pius and his clergy were ignorant of Nazi Germany's genocidal actions.
Historians have accused Pius XII of not only doing very little to curtail the Nazis, but of turning a blind eye to the so-called "ratlines" that some Catholic clergy helped set up for Nazi war criminals to flee Europe.
While it is unknown how much involvement Catholic clergy had with specific escapees, the Nazi war criminals Joseph Mengele, Klaus Barbie and Walther Rauff escaped Europe via ratlines.
Barbie, who was responsible for the torture and murder of French resistance fighters, was assisted in his escape by American intelligence, who saw him as a potential ally against the Soviet Union.
While Pius XII is known to have, at times, publicly opposed Nazi racial laws and discrimination against Jews, and many Catholic churches protected Jews, sometimes on Pius XII's orders, his church also frequently refused to denounce specific Nazi actions.