The exact number is unknown - varying according to different Ukrainian and international sources - but Kyiv alleges the executions reveal a deliberate policy by Moscow .
Authorities in the western city of Dortmund allege the brutal crimes took place between December 1943 and September 1944, prosecutor Andreas Brendel said.
One of the greatest yet most unheralded fighting units of World War II was so audacious, it made Steve McQueen and his band of POWs in The Great Escape look like amateurs.