The question has often been asked: When did the Allies learn about the concentration camps and what did they know about them? This document from the Supreme Headquarters Allied Expeditionary Force (SHAEF) files proves the Allies knew quite a lot about the Mauthausen death camp and its subcamp Gusen by July 1942. A table also is included showing what was known about food rations in Warsaw in 1941.
Click here to read the document.
Source: Paul Sturman Papers, Box 3, Poland (3); NAID #7330178], Dwight D. Eisenhower Presidential Library