Pope Pius XII, who led the Catholic Church from 1939 to 1958, has been criticized for public silence during the years of World War II and the Holocaust. A letter that a trusted Jesuit priest sent on Dec. 14, 1942 reveals that the pope—or at least, the papal secretary—was notified about the Nazi plot to murder Jews.

Pope Pius XII on the veranda at St. Peter’s Basilica in Rome after his election, March 2, 1939. Photo courtesy of the Brazilian National Archives via Wikimedia Commons.

Published in an Italian newspaper and slated to appear in a forthcoming book, the correspondence included information about ovens and crematoria, and about the Germans gassing up to 6,000 Jewish and Polish individuals daily in camps based in Poland.

“The documentation undercuts the Holy See’s argument that it couldn’t verify diplomatic reports of Nazi atrocities to denounce them,” the Associated Press reported.

Both the author of the letter, Rev. Lothar Koenig, and the recipient, Rev. Robert Leiber, were German Jesuits. The German letter reported “that the Nazis were killing up to 6,000 Jews and Poles daily from Rava Ruska, a town in pre-war Poland that is today located in Ukraine, and transporting them to the Belzec death camp,” per the AP.

The AP notes that the existence of the letter doesn’t prove that the pope was aware of its contents.

Still, “Leiber was Pius’ top aide and had served the pope when he was the Vatican’s ambassador to Germany during the 1920s, suggesting a close working relationship especially concerning matters related to Germany,” per the wire.

The Catholic Church recently beatified a Polish family murdered while hiding and sheltering Jews during