The impression I have is that a lot of former nazis were allowed to move to South America unmolested as a price tag for making Germany governable.
Not only South America. Almost 10 000 Nazis settled in U.S. of A. Many of them were part of Operation Paperclip. The entire speace program was run by them. Think of symbolism V1, V2, SATURN V
Many of them were war criminals responsible for deaths of thousands of people.