The Hitler ( of Nazi Party ) was mainly responsible for persecution of Jews. Historians stress the continuity between his ideas (against the Jews ) in early 1920s and the actual policies that he adopted in 1930s and early 1940s. Nazis were anti-Semitic because they regard Jews as threat to German Nation and responsible for defeat of Germany in WW1.
The moment Hitler became dictator of Germany, his supporters took it as a licence to persecute the Jews. We see in 1933, the Nazis ordered the boycott of Jewish shops. In 1935 Hitler propagated that there is a Jewish/Communist conspiracy to take control. The people fell to propaganda and began to loot, murder and persecute Jews. In the same year, the anti-Semitic campaign was legalized by the Nuremberg Laws (1935) which deprived Germans of their German citizenship and prohibit them to marry non-Jews. In 1938 we see Kristallnacht ( the Night Of Broken Glasses), a vicious attack on Jewish Synagogues and their property throughout Germany.
During the second World War the plight of the Jews further deteriorated. They were harassed in every possible way and were herded into concentration camps. Eventually Hitler came with a 'Final Solution' of Jewish problem i.e to wipe them off face of earth. At the end of World War Second more than 5 million Jews were murdered -most of them in gas chambers of Nazi extermination camps. This Holocaust , as came to be known, was the worst and most shocking of the many crimes against humanity committed by Nazi regime.
