You mean the people of that town couldn't have surmised just by the smell? The camp wasn't that far out of town ... they knew, they knew .....
The opening statements in this documentary tell it all. (Woman’s voice talking about how no one was ever a supporter of Hitler but no one ever denounced anyone else for what was done in their name)
https://www.youtube.com/watch?v=0KG74s4DnRw
Hard to believe no one from the town worked in the camp or no one from the camp was housed in town.
In their hearts and inner selves they knew what was going on at Dachau and elsewhere. It was the righteous indignation of US troops that forced them to deal with it up close and personal. Some commanders made the locals tour the camp. Some commanders made the local citizenry dig mass graves for the camps dead. More than a few locals after seeing what was done in their name killed themselves rather than have to deal with the shame and guilt. You’re right, they knew. But until the American troops arrived they did an awful good job of deceiving themselves.
CC