1939: The US government received reports from various diplomatic and intelligence sources about Nazi persecution of Jews, including the establishment of concentration camps, mass arrests, and the segregation and humiliation of Jewish people.
1942: More detailed reports and eyewitness accounts of the atrocities began to reach the US, including information from escaping prisoners, Polish underground resistance, and Jewish organizations.
January 1942: The US Treasury Department received a report known as the "Riegner Telegram" from Gerhard Riegner, a representative of the World Jewish Congress in Switzerland. This telegram warned of an ongoing "final solution" to exterminate the Jews.
December 1942: The US State Department received a report from the Polish government in exile, known as the "Polish White Paper," which detailed Nazi crimes against the Jewish population in occupied Poland.
November 1943: The US government intercepted and decrypted a German diplomatic message, known as the "Hoettl Telegram," which discussed plans for the mass deportation and extermination of Jews.
Despite increasing awareness of the Nazi atrocities and growing evidence, some key figures in the US government, including President Franklin D. Roosevelt and Secretary of State Cordell Hull, were reluctant to take decisive action or speak out publicly against the persecution of Jews.
It was not until the liberation of Nazi concentration camps in 1944-1945 and the subsequent uncovering of the full extent of the Holocaust that the true horror and magnitude of the genocide became widely known to the American public and the world.