Historians differ on the date of the decision to murder Jews systematically, the so-called “final solution to the Jewish question.” There is debate about whether there was one central decision or a series of regional decisions in response to local conditions. In either case, when Germany attacked the Soviet Union, its former ally, in June of 1941, the Nazis began the systematic killing of Jews.
Further trials at Nuremberg took place between 1946 and 1949, which tried another 185 defendants.[460] West Germany initially tried few ex-Nazis, but after the 1958 Ulm Einsatzkommando trial, the government set up a governmental agency to investigate crimes.[461] Other trials of Nazis and collaborators took place in Western and Eastern Europe. In 1960, Mossad agents captured Adolf Eichmann in Argentina and brought him to Israel to stand trial on 15 indictments, including war crimes, crimes against humanity, and crimes against the Jewish people. He was convicted in December 1961 and executed in June 1962. Eichmann's trial and death revived interest in war criminals and the Holocaust in general.[462]
Peter Longerich argues that the search for a finite date on which the Nazis embarked upon the extermination of the Jews is futile, in his book Holocaust: The Nazi Persecution and Murder of the Jews (2011). Longerich writes: "We should abandon the notion that it is historically meaningful to try to filter the wealth of available historical material and pick out a single decision" that led to the Holocaust.[116][117]
Despite having provided Mengele with legal documents using his real name in 1956 (which had enabled him to formalize his permanent residency in Argentina), West Germany was now offering a reward for his capture. Continuing newspaper coverage of Mengele's wartime activities, with accompanying photographs, led him to relocate once again in 1960. Former pilot Hans-Ulrich Rudel put him in touch with the Nazi supporter Wolfgang Gerhard, who helped Mengele to cross the border into Brazil.[78][86] He stayed with Gerhard on his farm near São Paulo until more permanent accommodation could be found, with Hungarian expatriates Geza and Gitta Stammer. With the help of an investment from Mengele, the couple bought a farm in Nova Europa, which Mengele was given the job of managing for them. The three bought a coffee and cattle farm in Serra Negra in 1962, with Mengele owning a half interest.[87] Gerhard had initially told the Stammers that Mengele's name was "Peter Hochbichler", but they discovered his true identity in 1963. Gerhard persuaded the couple not to report Mengele's location to the authorities, by convincing them that they themselves could be implicated for harboring the fugitive.[88] In February 1961, West Germany widened its extradition request to include Brazil, having been tipped off to the possibility that Mengele had relocated there.[89]

The Nazis then combined their racial theories with the evolutionary theories of Charles Darwin to justify their treatment of the Jews. The Germans, as the strongest and fittest, were destined to rule, while the weak and racially adulterated Jews were doomed to extinction. Hitler began to restrict the Jews with legislation and terror, which entailed burning books written by Jews, removing Jews from their professions and public schools, confiscating their businesses and property and excluding them from public events. The most infamous of the anti-Jewish legislation were the Nuremberg Laws, enacted on September 15, 1935. They formed the legal basis for the Jews' exclusion from German society and the progressively restrictive Jewish policies of the Germans.
At each of the death camps, special squads of Jewish slave laborers called Sonderkommandos were utilized to untangle the victims and remove them from the gas chamber. Next they extracted any gold fillings from teeth and searched body orifices for hidden valuables. The corpses were disposed of by various methods including mass burials, cremation in open fire pits or in specially designed crematory ovens such as those used at Auschwitz. All clothing, money, gold, jewelry, watches, eyeglasses and other valuables were sorted out then shipped back to Germany for re-use. Women's hair was sent to a firm in Bavaria for the manufacture of felt.
Belzec, Sobibor, and Treblinka formed part of what the Nazis called “Operation Reinhard,” whose sole purpose was the systematic massacre of Jews. A labor camp existing in Belzec since 1940 was turned into an extermination camp in the autumn of 1941, becoming operative in March 1942. In the same month, the camp at Sobibor was set up to alleviate the overburdened camp of Belzec. The third, Treblinka, received the Jews from Warsaw and the Radom district.
The twins were then tattooed and given a number from a special sequence. They were then taken to the twins' barracks where they were required to fill out a form. The form asked for a brief history and basic measurements such as age and height. Many of the twins were too young to fill the form out by themselves so the Zwillingsvater (twin's father) helped them. (This inmate was assigned to the job of taking care of the male twins.)
Holocaust scholar and Christian ethicist David Gushee highlighted other traits in his book, Righteous Gentiles of the Holocaust. “Some rescuers appear to have been adventuresome types, and others drew upon a sense of social marginality as a resource for compassion. Another mark of rescuer character is the nearly universal unwillingness to accept praise for their deeds. ‘It is what anyone would have done,’ they say of behaviour that almost no one did. For them to rescue Jews was the perfectly natural and obvious course of action. People needed help. So help was offered.”
The Nazis established ghettos in occupied Poland. Polish and western European Jews were deported to these ghettos. During the German invasion of the Soviet Union in 1941, mobile killing squads (Einsatzgruppen) began killing entire Jewish communities. The methods used, mainly shooting or gas vans, were soon regarded as inefficient and as a psychological burden on the killers.

Righteous Among the Nations (Hebrew: חֲסִידֵי אֻמּוֹת הָעוֹלָם, khasidei umót ha'olám "righteous (plural) of the world's nations") is an honorific used by the State of Israel to describe non-Jews who risked their lives during the Holocaust to save Jews from extermination by the Nazis. The term originates with the concept of "righteous gentiles", a term used in rabbinic Judaism to refer to non-Jews, called ger toshav, who abide by the Seven Laws of Noah.
In June 1941, Mengele was posted to Ukraine, where he was awarded the Iron Cross 2nd Class. In January 1942, he joined the 5th SS Panzer Division Wiking as a battalion medical officer. After rescuing two German soldiers from a burning tank, he was decorated with the Iron Cross 1st Class, the Wound Badge in Black, and the Medal for the Care of the German People. He was declared unfit for further active service in mid-1942, when he was seriously wounded in action near Rostov-on-Don. Following his recovery, he was transferred to the headquarters of the SS Race and Settlement Main Office in Berlin, at which point he resumed his association with von Verschuer, who was now director of the Kaiser Wilhelm Institute of Anthropology, Human Heredity, and Eugenics. Mengele was promoted to the rank of SS-Hauptsturmführer (captain) in April 1943.[20][21][22]