A Nazi hunter is an individual who tracks down and gathers information on alleged former Nazis, or SS members, and Nazi collaborators who were involved in the Holocaust, typically for use at trial on charges of war crimes and crimes against humanity. Prominent Nazi hunters include Simon Wiesenthal, Tuviah Friedman, Serge Klarsfeld, Beate Klarsfeld, Ian Sayer, Yaron Svoray, Elliot Welles, and Efraim Zuroff. History With the onset of the Cold War following World War II, both the Western Allies and the USSR sought out former Nazi scientists and operatives for programs such as Operation Paperclip and Operation Osoaviakhim. Cooperative former Nazis, such as Wernher von Braun and Reinhard Gehlen, were occasionally given state protection in return for valuable information or services. At the time, Gehlen had been chief of the German Federal Intelligence Service or Bundesnachrichtendienst (federal intelligence agency), founder of the Gehlen Org, "a true life version of ODESSA" network, which helped exfiltrate Nazis from Europe. Other Nazis used ratlines to escape post-war Europe to places such as South America. In response, Nazi hunters sought out fugitives on their own or formed groups, such as the Simon Wiesenthal Center. Methods used by Nazi hunters include offering rewards for information, reviewing immigration and military records, and launching civil lawsuits. In later decades, Nazi hunters found greater cooperation with Western and South American governments and the state of Israel. By the end of the 20th century, pursuit of former Nazis declined, because most of the generation active in Nazi leadership had died. Notable targets The Simon Wiesenthal Center publishes an annual report on Nazi war criminals. Some notable targets of Nazis hunters have included: Klaus Barbie, the "Butcher of Lyon", was extradited from Bolivia to France in 1983, after earlier attempts by Serge and Beate Klarsfeld to track him. Until Bolivia's transition to democracy, he had been protected by the US and German intelligence services for anti-Soviet intelligence purposes, and employed by the Bolivian army under an alias. Sentenced to life imprisonment in 1987, he died in 1991. Herberts Cukurs, the "Butcher of Riga", was assassinated by Mossad agents in Montevideo, Uruguay in 1965. Adolf Eichmann was pursued by Wiesenthal before being captured and smuggled from Argentina in 1960 by the Israeli spy agency, Mossad, and was tried in Israel, where he was executed in 1962. Boļeslavs Maikovskis, a Latvian Nazi collaborator, was pursued to Mineola, New York by Welles. Maikovskis