As of 2008, OSI has successfully prosecuted 107 Nazi persecutors. OSI has also worked closely with the Department of Homeland Security to stop more than180 former European and Japanese Axis perpetrators and suspected perpetrators of acts of persecution at U.S. ports of entry and bar them from entering the United States.

In addition to the well-known Nuremberg Trials of 1945-46 [of 22 defendents], there were Subsequent Nuremberg Proceedings held between December 1946, and April 1949, which tried 177 persons. Individual countries also prosecuted war criminals in national courts of law. The British held trials of the commandant and staff of the Bergen-Belsen camp, those responsible for forced labor, and the owners and executives of the manufacturer of Zyklon B, among others. The Netherlands, Hungary, Norway, Poland, West Germany, and Romania were some of the other countries that brought war criminals to trial.

Let us look, if you will, just at the past month, February 2000. In one month, my office won two prosecutions. One at the United States Board of Immigration Appeals, the other, two weeks ago, at the United States Supreme Court, involving the case of former Auschwitz SS man Ferdinand Hammer. The Canadian government, just last week, won its citizenship case against Helmut Oberlander, a member of a mobile killing unit. And just last month, the British authorities won the appeal of the Sawoniuk case, a Ukrainian perpetrator, at the High Court in London. And only a few months ago the Croatian government, which frankly had to be dragged kicking and screaming into this prosecution, successfully prosecuted Dinko Sakic, the former commandant of the Jasenovac concentration camp.

After World War II, centres, commissions and offices were established with the purpose of bringing Nazi war criminals to trial. They collect information, investigate crimes, pass on names of Nazis to their respective governments and take action against Nazi criminals in their own countries.

‘Zentrale Stelle Ludwigsburg’ is Germany’s documentation centre, which collects evidence for the prosecution of crimes committed during the nazi regime in the period 1933-1945.

Immediately after World War II, the provisional Polish government established the ‘Central Commission for Investigation of German Crimes in Poland’. The main commission has since then investigated nazi crimes committed in Poland during World War II and these days exist under a different name, the 'Main Commission for the Investigation of Crimes against the Polish Nation'....

The ‘Simon Wiesenthal Center’ in Vienna, founded by the Nazi-hunter Simon Wiesenthal, is perhaps the most famous documentation centre. Since World War II, the centre has tracked down many Nazi war criminals.

Poland was relatively quick to convict the camp personnel from Auschwitz – at least those that could be found. Trials were initiated against at least 600 members of the Auschwitz camp personnel. Among these were the two camp commandants, Rudolf Höss and Arthur Liebehenschel, who were sentenced to death in 1947. Rudolf Höss was hanged in Auschwitz in 1941. A total of 21 were executed....

In West Germany the so-called Auschwitz Trials were conducted against the camp guards from the concentration and extermination camp at Auschwitz. The largest of these trials took place in Frankfurt am Main between 1963 and 1965, where 20 were accused. 17 were given jail sentences....

On 3 July 1964 twelve of the personnel in the extermination camp Sobibor stood accused of participating in the murder of Jews in the camp. All twelve were accused of assisting in the killings. The trial itself began in Hagen on 6 September 1965 and ended on 20 December 1966. More than 100 witnesses were called.

The overwhelming majority of post-1945 war crimes trials involved lower-level officials and functionaries. In the immediate postwar years, the four Allied powers occupying Germany (and Austria) -- the United States, Great Britain, France, and the Soviet Union -- held trials in their zones of occupation and tried a variety of perpetrators for wartime offenses. Many of the earliest zonal trials, especially in the U.S. zone, involved the murder of Allied military personnel who had been captured by German or Axis troops. In time, however, Allied occupiers expanded their juridical mandate to try concentration camp guards and commandants and others who had committed crimes against Jews and others who suffered persecution in areas the Allies now occupied. Much of our early knowledge of the German concentration camp system comes from the evidence and eyewitness testimonies at these trials....

Allied Control Council Law No. 10 of December 1945 authorized German courts of law to pass sentence on crimes committed during the war years by German citizens against other German nationals or against stateless persons. For this reason, occupation officials left Euthanasia crimes -- where both victims and perpetrators had been predominantly German nationals -- to newly reconstructed German tribunals. These proceedings represented the first German national trials in the early postwar period. Both the German Federal Republic (West Germany) and the German Democratic Republic (East Germany) continued to hold trials against Nazi-era defendants in the decades following their establishment as independent states. To date, the Federal Republic (in its old manifestation as West Germany and in its current status as a united Germany) has held a total of 925 proceedings trying defendants of National Socialist era crimes. Many detractors have criticized German proceedings, particularly those held in the 1960s and 1970s, for doling out acquittals or light sentences to aging defendants or defendants who claimed superior orders.

Many nations which Germany occupied during World War II or who collaborated with the Germans in the persecution of civilian populations, especially Jews, have also held national trials in the years following World War II. Poland, the former Czechoslovakia, the Soviet Union, Hungary, Romania, and France, among others, have tried thousands of defendants -- both Germans and indigenous collaborators, in the decades since 1945. The Soviet Union held its first trial, the Krasnodar Trial, against local collaborators in 1943, long before World War II had ended. Perhaps Poland's most famous postwar national trial was held in 1947 in Krakow. The proceedings tried a number of functionaries of the Auschwitz concentration camp and sentenced Auschwitz camp commandant Rudolf Höss and others to death.