the war, hocker had been a struggling bank teller, becoming an s.s.e majdanek camp before this. he had experience with gas chambers. he signed receipts the record zyklon b, the lethal gas that was used for killing people. he is a crucial cog in the nazi killing machine. >> the 116 photos in the album show auschwitz has karl hocker wanted to remember it. >> it's a mix of candid things and really official. this is his dog. his dog's name is favorit. >> what's stunning is how -- >> normal? >> yeah. >> yeah. >> who hasn't taken a photo of them shaking their dog's hand. this is 1944, nazi christmas. they know the soviets are coming. they are not far. they can probably hear the bombs. >> and they're lighting christmas -- >> yeah. >> the album reveals something else museum officials hadn't seen before. the nazis built a vacation resort at auschwitz. it was called solahutte. these pictures show a gathering of top s.s. officers there in july of 1944. rebecca erbelding believes it was a party. they were congratulating themselves for successfully murdering more