Nazi Criminals were tracked through the effort of various organizations and secret services who worked worldwide on finding information on rogue Nazis. Many Nazis changed their names and countries and lived in hiding but they used their resources to track them down by getting information from various sources such as Governments or other people or other spies.
The charges were crimes against humanity, crimes against peace, war crimes, and conspiracy to commit any of the other crimes. These four charges however do have a detailed description as to what they entail and what each charge constitutes and according to these four charges the caught Nazis were put on trial.
The trials were organized in waves according to the degree of participation in the war crimes. The first trial was the most famous one since it put on trial famous high ranked Nazis who organized everything. Later trials included trials against doctors, or against the railway, or against other organizations that participated indirectly and directly
