Reddit mentions of The Unknown Dead: Civilians in the Battle of the Bulge

Not even the camps, just the regular extermination as the army moved through towns. When Allied nations took back land, they were met with fanfare and parades. When the Germans moved through a town, they started killing civilians.

Like during the bulge. When the allies were pushed out of the Ardennes and the Germans started controlling some towns again, what did they do? They took the opportunity to start massacring some Belgians again! Right there on the spot. No need to ship then across Germany, they didn't have the time so they took what they were given, and made the best of it before the allies returned. The Germans were efficient if anything. These weren't just those tricksy SS units going around doing some bad stuff all sneaky like. The regular military regularly did horrific things when they had the chance. There was no soldier in the wehrmacht who didn't have an idea of what was required of him when asked, and what was routinely asked for.

The worst the allies ever did was occasional bloodthirsty soldiers shooting POWs. But these are memorable and recorded specifically because they would try to stop each other, they know about the Geneva Conventions, and the people were prosecuted afterwards.