Within five months of Nazi Germany's invasion in the summer of 1941, most of Lithuania's 200,000 to 220,000 Jews were dead -- shot and left in massive sand pits and mass graves along with thousands of ethnic Poles, the mentally ill and others. By the end of the war, the percentage of Jews killed in Lithuania -- 90 to 96 percent -- was as high or higher than anywhere else in Europe.
"And the question is, 'Why were the numbers so high?' And here we come to a subject that is very, very delicate and difficult," says Efraim Zuroff, who’s great-uncle was kidnapped in Vilnius, Lithuania, on July 13, 1941, by a gang of Lithuanians "roaming the streets of the city looking for Jews with beards to arrest.".
"One of the main reasons so many Jews were killed here is because of the help of the local population -- of the Lithuanians."
The pace of the mass murder of Lithuania's Jews -- and the active participation of the local population -- are meticulously recorded in two of the most infamous documents of Holocaust history.
The Jaeger Report, written by Karl Jaeger, the SS commander of a Nazi killing unit that operated around Vilnius, Lithuania, is a matter-of-fact account of those killed each day under his command.
September 1, 1941, a typical entry, lists those killed for the day as: "1,404 Jewish children, 1,763 Jews, 1,812 Jewesses, 109 mentally sick people, one German woman who was married to a Jew, and one Russian woman."
Read: The Holocaust in Lithuania: One man's crusade to bring justice on CNN.com (with video)