There was a concentration camp near my hometown in Germany. It was a “work camp” not a “destruction camp”, which just meant they had no gas chambers and people were murdered through extremely hard labour in a quarry. The museum there has a collection of letters that show the interactions between ordinary people and the camp authorities. As far as I remember they had the following conversations on display:

• people asking for forced labourers for their private projects
• camp authorities reprimanding the public not to leave potato skins and other leftover food out when prisoners were marched through town
• people compalining about the stench, thick, oily smoke, as well as blood and bits of bone in the creek

People saw a lot and people talked