That is an intellectually dishonest question. By hinging the connection solely on the use of the word "evolution", you give yourself on out when presented with info that contradicts your world view.
Wasn't the NAZI practice of eugenics nothing more than an industrialized form of Darwinism put into action?.
If the question is what inspired the Nazi's to carry out the Holocaust, then is it not of primary import to look at the words Nazi leaders used to justify mass murder to the masses? Not secret notes unpublished during Hitler's lifetime, not what secrets lay deep in Hitler's heart; what words were actually used to inspire and justify the Holocaust.
Eugenics was justified in the last century due to the misapplication of Evolution to think that somehow natural selection was not at work among humans (it is); however Eugenics was practiced long before Darwin ever published.
Saying that Eugenics was dependent upon Darwin (rather than just seeking justification under its auspices) is like saying that selective breeding of dogs was dependent upon Darwin; ignoring that the principles and concepts of selective breeding were well known throughout human history. Eugenics is nothing more than selective breeding of humans, and selective breeding has been going on for many thousands of years of human history.