Garry Wills covered this subject in "Papal Sin," published in 2000. In brief, the Vatican had accurate week-by-week totals of the number of people shipped to death camps. The numbers came from village priests, Catholic railway workers, Catholic Nazis. One week after the liberation of Rome on June 4, 1944, the US envoy met with the pope. The pope was asked to announce a ban on Catholic participation in the deportation/murder of Jews. By 1944, the 3 million Jews of Poland were dead, but there remained 800,000 Jews in Hungary. The US hoped that the pope would make an effort to save them, now that the Nazi threat to the Vatican was removed. The pope refused. Garry Wills believes that the pope wanted a Jew-free, 100% Catholic Hungary, after the war. If the Nazis did the dirty work....good.
We should never canonize a person who made no effort to stop the persecution and killing of the 4 million Jews! "Not speaking out" is not the only issue! Actually being friendly with the Nazis who killed and only showing sensitivity about converted Jews shows how inhumane Pope Pius XII was! If he is a saint, then beatify Mussolini!!!
Did Pius himself ever say that he didn't know? Who's saying he didn't know? Obviously he would have done otherwise he wouldn't have sheltered thousands of Jews in church properties during these times.
Probably Pius knew because different people in different positions within the iglecia católica gave him in details the all necessary happening but choose to keep looking the other way the peace time period in order to save la iglesia católica !!! He avoided any open confrontation with the corporal because he was afraid the consequences , he was afraid that may moved in Vatican & crushed it & everything else puts in ruins so he couldn't handle the situation & choose the suffering of the Christian & Jew people as well as the humiliation !!!