Major Gerhard Engel was Hitler’s Army Adjutant. His diary records how the Fuhrer ['F'] reacts to a report describing atrocities in Poland:
Siewert sent for me and handed me a memorandum from Gen. Blaskowitz about the situation in Poland; serious concern about illegal shootings, arrests and seizures. Worries about Army discipline amongst those who see these things going on; local discussions with SD [Sicherheitsdienst - Security Service] and Gestapo unsuccessful, they refer back to orders from Reichsfiihrer-SS. Please, restore rule of law, above all only carry out executions which result from proper judicial proceedings.
Submitted the memo, which is precisely factual, to F. the same afternoon. He read through it calmly then lashed out furiously against ‘infantile attitude’ in Army High Command. The war couldn’t be run with Salvation Army methods. A long-held aversion came to light. He had never trusted Gen. Bl. He had been opposed to giving him command of an army, and considered it right to relieve him of it since he was unsuitable.
There is some debate about when the first memorandum from Blaskowitz was received, although Engel records it in his diary on the 18th November. Blaskowitz submitted further memoranda and was eventually relieved of his command in May 1940.
See Major Gerhard Engel: At the Heart of the Reich: The Secret Diary of Hitler’s Army Adjutant also available from amazon.com and amazon.ca.