is it true that German solders killed 4000 polish officers at the end of ww2 in warsaw poland?

Answer 1

I believe the incident you are referring to is the Katyn Forest Massacre where 4000 Polish officers were massacred, not by the Nazis, but by the Soviets on Stalin's order in late 1939 or early 1940. Most people forget that in 1939, Poland was invaded by Nazi Germany first and then by the Soviet Union about 18 days later. Half of Poland was occupied by the USSR, the other half by the Nazis.

Stalin wished to eliminate any leaders among the Poles that could cause trouble in his part of occupied Poland. Remember that at this point in time, the USSR and the Nazis signed a non-aggression pact and were somewhat defacto allies until Germany invaded the Soviet Union in June 1941.