There was Klaus Barbie, head of the Gestapo in Lyon from 1942 to 1944, who came to be known as the "Butcher of Lyon" for his cruelty. There was also Kurt Lischka and Herbert Hagen, who were responsible for the deportation of 76,000 Jews from France to extermination camps, among them 11,400 children. These are just three of the many Nazi war criminals and collaborators who have been tracked down by well-known Nazi hunters Serge and Beate Klarsfeld.

Their life's work has ensured that these three perpetrators were convicted of their crimes, yet so many other Nazis have, despite committing many atrocities, managed to live out their lives in peace.

Serge Klarsfeld, a lawyer and Holocaust survivor himself, described their investigative strategy in simple terms: "We only pursued the criminals who had made decisions about the fate of masses of Jews," he wrote to DW. "We only pursued the leaders of the Final Solution. Our search for and involvement in the arrest of Barbie after a 12-year struggle from 1971 to 1983 earned us great acclaim in France."

The spectacular discovery of Barbie in Bolivia was also lauded in Germany, which for decades had limited its search for perpetrators of the Holocaust to just a few leading figures. The Klarsfelds later

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