Source: Two entries in late 1940 in William Shirer's Berlin diary.
Comment: Written or prepared for publication in early 1941 it must represent one of the earliest descriptions of "Mercy Killings" in the Allied public sphere. Quite accurate in identification of 3 of the 6 major locations, but not accurate at all in his description of the genesis of the scheme.
Berlin, September 21 1940
X came up to my room in the Adlon to-day, and after we had disconnected my telephone and made sure that no one as listening through the crack of the door to the next room he told me a weird story. He says the Gestapo is now systematically bumping off the mentally deficient people of the Reich. The Nazis call them "mercy deaths". He relates that Pastor Bodelschwingh, who runs a large hospital for various kinds of feeble-mined children at Bethel was ordered to be arrested a few days ago because he refused to deliver up some of his more serious mental cases to the secret police. Shortly after this, his hospital is bombed. By the "British". Must look into this story.
Source: America Views the Holocaust, page 183-191. Polish Death Camp: Collier's, October 14, 1944
Comment: Useful to demonstrate that visiting Izbica is not a viable explanation for Karski's testimony