He was born in Völlen, near the border with the Netherlands. In 1931, at the age of 19, he entered the NSDAP, and three years later joined the ranks of the SS. Quickly, he got assigned first to the Esterwegen camp, and then to the Sachsenhausen camp near Berlin. We do not know much about his deeds at the time. However, it is known that in 1941 he was assigned to action “T4” – an operation to murder the disabled and mentally ill.

His career was gaining momentum. When Operation Reinhardt was carried out in the General Government, Johan Niemann was sent to occupied Poland, where new extermination centers were being established. The young SS man was first sent to Belzec, where Camp II was just being organized, which was an extermination zone, i.e. a place where gas chambers and mass graves were located. Niemann had a close relationship with camp commandant Christian Wirth, which may have been the reason for his transfer to the Sobibor camp. There, Johan Niemann became deputy commandant. In the spring of 1943, he was promoted to the rank of Untersturmführer (SS lieutenant).

On the day the camp mutiny broke out, Johan Niemann was the highest-ranking officer, so he became the first target to be eliminated by the prisoners. He was lured by Jews from a group sorting clothes from the murdered into the shed to try on a leather jacket that had been set aside for him. When he went inside, Alexander Shubayev, a Jewish soldier in the Red Army, killed him with an axe blow to the head.

Many years after the war, in 2015, Niemann’s family found two albums of photographs he had taken. Among the surviving photographs were those documenting the activities of the Esterwegen camp, depicting the author’s participation in Operation “T4,” and about the camps in Belzec and Sobibor. The collection was donated to the United States Holocaust Memorial Museum.