On 30 January 1933, Adolf Hitler was appointed Chancellor of Germany, and the Nazi movement began its seizure of the state. Political opponents were arrested, rival parties were destroyed, and thousands were sent to prisons or temporary detention centers that, within months, became a permanent system of concentration camps designed to isolate anyone the regime considered an enemy. At first, most prisoners were communists, social democrats, and other political opponents. Over time, Jews, Roma, Jehovah’s Witnesses, men persecuted for their sexual orientation, and many others were also imprisoned.
The camps became places of forced labor, starvation, torture, and murder, but they also created career paths for men willing to carry out that violence. One of them was a former clerk and Great War veteran who served in several early camps before becoming commandant of Sachsenhausen and then Buchenwald, where he gained almost unlimited power over thousands of prisoners. He exploited them, stole their property, and ordered the killing of witnesses who could expose him. His brutality did not trouble his superiors, but his greed eventually crossed a line they could no longer ignore.
Before the collapse of Nazi Germany, he would pay for his crimes with his life. His name was Karl Otto Koch. Karl Otto Koch was born on 2 August 1897 in Darmstadt, then part of the German Empire. His father worked in the local registry office but died in 1905, when Koch was only eight years old.
After leaving school in 1912, he completed commercial training and worked as a clerk. Although the First World War began in 1914, Koch did not volunteer for the Imperial German Army until two years later. He fought on the Western Front, where he received, among other decorations, the Iron Cross Second Class, a German military award given for bravery and distinguished service. British forces captured him in 1918, and he remained a prisoner of war until he returned home the following year.
Koch then found work in banking and insurance. In 1924, he married Katharina Müller, and the couple had two sons, Manfred and Alfred. His frequent affairs led to their divorce in 1931. That same year, Koch joined the Nazi Party and the SS, the paramilitary organization created to protect Adolf Hitler and other Nazi leaders, which was gradually expanding its role within the movement.
After the Nazis came to power in 1933, Koch’s SS membership gave him the career and authority he had never possessed before. He entered the rapidly expanding concentration camp system and spent the following years serving in several early detention centers. Koch also joined the SS-Totenkopfverbände, or Death’s Head Units, which were responsible for guarding and administering concentration camps and later extermination camps. While serving in Saxony in central Germany in 1934, he met Margarete Ilse Köhler, a secretary from Dresden nine years his junior who had been a Nazi Party member since 1932.
Koch continued his rise, and in 1936 he became commandant of Sachsenhausen concentration camp, built near the town of Oranienburg north of Berlin. His position gave him almost unlimited authority over the prisoners held there. Ilse followed him to Sachsenhausen, and the couple married at the camp on 25 May 1937. They had three children, a son named Alvin and two daughters, Gisela and Gudrun, but Gudrun died of pneumonia in February 1941 when she was only four months old.
Seven weeks after the wedding, Koch left Sachsenhausen to command Buchenwald, a new concentration camp near the city of Weimar in central Germany. On 15 July 1937, the SS transported the first 149 prisoners there by truck from Sachsenhausen. By the end of the year, the camp held more than 2,500 men. They cleared trees, laid foundations, and built wooden barracks.
In the limestone quarry, prisoners broke stones with simple tools, pushed loaded carts, and were brutally beaten if they slowed down. Buchenwald was not an extermination center designed for mass killing in gas chambers. Instead, it imprisoned people the regime considered enemies or undesirables and subjected them to forced labor, hunger, disease, and violence outside the legal system. Yet this did not mean systematic killing was absent.
Prisoners were executed, killed by lethal injection, or worked and starved to death, while thousands of Soviet prisoners of war were later shot in a converted stable. One prisoner who survived the war recalled how Karl Otto Koch received them at Buchenwald. So, you are here now. Once you enter this camp, there is no way out.
Remember that. You will not leave here alive. The violence directed at new arrivals was part of a broader punishment system that threatened every prisoner at Buchenwald. Even the smallest alleged offense could lead to a public flogging, where victims were forced to count each blow aloud.
If they miscounted or could no longer speak, the guards often started over, and the beating could end in death. Other forms of torture took place away from the eyes of most prisoners, inside the camp prison known as the Bunker. Its twenty-six cells were rarely empty. Men held there were locked in darkness, forced to stand all day, or hung from the cell bars, or killed by lethal injection.
The same system that allowed such violence also gave Koch opportunities to enrich himself. He treated Buchenwald as his own estate, exploiting prisoners as unpaid labor and embezzling their money and property. Cash taken from new arrivals, confiscated valuables, and funds drawn from camp accounts helped finance the luxurious life he and Ilse built for themselves. The couple lived in a large villa furnished with expensive items, where prisoners worked as servants.
Koch also forced prisoners to build recreational facilities for camp staff and their families. In 1938, they created a zoo near the camp fence, housing monkeys, brown bears, and deer. It was funded with money prisoners were forced to surrender, while the animals received better food and care than the prisoners living nearby. In 1940, forced laborers built an indoor riding hall, where Ilse, later known as the Witch of Buchenwald for her cruelty toward prisoners, could train her horse in bad weather.
The Kochs grew rich through this exploitation and made little effort to hide their lifestyle. Koch’s treatment of prisoners did not disturb his superiors, but stealing from the SS eventually did. By 1941, suspicions grew about his manipulation of Buchenwald’s accounts and his diversion of money and property for personal gain. Walter Kremer, a prisoner who supervised the camp infirmary, knew how Koch was enriching himself.
He had also secretly treated the commandant for syphilis, a serious bacterial infection usually transmitted through sexual contact that could eventually destroy the brain, heart, and other organs. Koch had a history of extramarital affairs, although it is not known when or from whom he contracted the disease. Discovery would have humiliated him and could have damaged his standing in the SS, especially because he had relied on prisoners rather than official doctors for treatment. Kremer and his assistant Karl Peix knew both about the illness Koch wanted to hide and the financial crimes behind his wealth.
On 6 November 1941, the two men were taken to a subcamp of Buchenwald near Goslar, a town in central Germany, and shot from behind on Koch’s orders. Camp records falsely claimed they had been killed while attempting to escape. In December of that year, Josias, Hereditary Prince of Waldeck and Pyrmont, the police and SS commander responsible for the region containing Buchenwald, arrested Koch on corruption charges, but Heinrich Himmler, the head of the SS, ordered his release shortly afterward. However, Karl Otto Koch was removed from Buchenwald and sent to Eastern Europe, while his wife Ilse remained there with their children in the SS settlement.
In January 1942, Koch became commandant of a new prisoner-of-war camp near Lublin in German-occupied Poland. This camp later became the Lublin concentration camp, known as Majdanek, and turned into a site of forced labor and mass murder. When Koch arrived, the complex was still under construction. About 2,000 Soviet prisoners of war were forced to build its barracks and fences while sleeping outdoors with almost no food, and most died within weeks.
Conditions remained appalling, while a shortage of guards and their poor training left parts of the camp insufficiently secured. On 14 July 1942, 86 Soviet prisoners escaped. Koch blamed the lack of resources and his staff, but he was held responsible and relieved of command the following month. He was transferred to administrative work and later served as a liaison officer between the SS and the German postal service.
While Koch held this new position, Josias continued examining the records left behind at Buchenwald. In the list of dead prisoners, he found the name Walter Kremer and recognized it immediately. Kremer had successfully treated him before, and the claim that he had been shot while attempting to escape now seemed suspicious. In 1943, the investigation was placed in the hands of Georg Konrad Morgen, a lawyer and judge in the SS court system.
He examined camp accounts, property records, and prisoner deaths that had no explanation. Large sums of money, about 100,000 Reichsmarks, were found in Koch’s private accounts, far more than his salary could justify, while other evidence revealed theft of jewelry, gold, and valuables. Morgen also linked the former commandant to the murders of Kremer, Peix, and another prisoner killed to prevent them from speaking. On 24 August 1943, Koch returned to the family villa next to Buchenwald, where investigators were waiting.
Karl and Ilse were arrested that night. Karl Otto Koch had crossed a line the SS itself was not prepared to tolerate, not because of his treatment of prisoners, but because he had stolen from the organization itself and killed witnesses to hide his crimes. Himmler expected valuables taken from prisoners to be handed over to the state, not kept by officers for themselves. In September 1944, the trial against Karl Otto Koch began.
During the proceedings he said, I cannot explain my actions, except that my superiors corrupted me. Everything I proposed and did met with approval. I received only praise and honors. It went to my head.
I became paranoid at that time. On 19 December 1944, Karl Otto Koch was convicted of theft and ordering unauthorized killings and sentenced to death. Ilse was acquitted for lack of evidence and released after about sixteen months in custody. The expanded investigation also implicated Hermann Florstedt, one of Ilse’s lovers, who had served under Koch at Buchenwald before later becoming commandant of Majdanek.
Florstedt was convicted of corruption and murder and also sentenced to death. Koch remained in an SS prison in Weimar through the winter as American forces advanced toward central Germany. On 5 April 1945, the 47-year-old Karl Otto Koch was taken to Buchenwald concentration camp, the very place he had once commanded. His last words before an SS firing squad shot him were, Young men, aim well.
Only six days later, the camp was liberated by the American Sixth Armored Division. The fate of Karl Otto Koch’s family was no better. Melvin, his only son, could not live with the shame of his parents’ crimes and took his own life in 1967. Shortly afterward, Ilse Koch, who had been sentenced to life imprisonment twice after the war, hanged herself in her cell, leaving a note saying, I cannot help myself.
For me, death is liberation.