It is unclear when exactly Hitler decided to murder Europe’s Jews. The decision was probably made sometime in 1941, with the invasion of the Soviet Union. On January 20, 1942, Reinhard Heydrich, the chief of Germany’s Security Police, held a secret meeting known as the Wannsee Conference. Leading police and civilian officials discussed the continuing implementation of the "Final Solution." The Nazi leaders envisioned killing 11 million Jews as part of the “Final Solution.” They succeeded in murdering 6 million. Hope this helps!