There are three books I've read recently that address this specifically.

Between Dignity and Despair by Marion Kaplan.

Ordinary Men by Christopher Browning.

Hitler's Furies by Wendy Lower.

If you haven't read these, I would highly recommend them. Between Dignity and Despair and Ordinary Men are two of the best books I've ever read.

Kaplan's books looks at the daily lives of Jews in Germany from 1933-1945, and throughout the book she discusses the roles ordinary Germans played, coming to the conclusion that many Germans were complicit and participatory, and even though they might not have directly supported the Nazis, they did little to stop them.

Browning's book looks at a German reserve police battalion and their role in the Final Solution in Poland. He determines that most of the men in the battalion were simply doing what they thought they had to do. Some men, mainly officers, supported the Nazis, but it wasn't a widespread ideology.

Lower's book looks at German women in the east, and their role in the Final Solution. Again, a lot of women were simply doing their jobs, but there were some that Lower presents that supported the Nazis adamantly.