The Allies and the USA knew all about the Holocaust thanks to this man but kept it a secret. Total farce of a narrative that American troops 'discovered' concentration camps when they went into Germany.
There are a lot of silly lies about the War that have yet to be dispelled. Actually, a recent book that contributes to this effort is "First to Fight" by Roger Moorhouse[0].
[0] https://www.amazon.com/First-Fight-Polish-War-1939/dp/184792...