It was an extraordinary moment, Dr. Alexander would later testify, horrifying in its clarity. Neither of the tubs could possibly fit a submerged cow, horse, or large pig. What these tubs “could fit was a human being,” Dr. Alexander said.
The grim reality of Dr. Weltz’s Luftwaffe research became painfully clear. “I came away from all these interviews with the distinct conviction that experimental studies on human beings, either by members of this group themselves, or by other workers well known to and affiliated [with] the members of this group, had been performed but were being concealed,” Dr. Alexander wrote. Without an admission of guilt, he had only suspicion. To make an arrest, he needed evidence. He thanked Dr. Weltz for his assistance and told him that he would be returning sometime in the future for a follow-up visit.
Dr. Alexander had been on German soil for two weeks, and the deviance of Nazi science overwhelmed him. In a letter to his wife, Phyllis, he described what had become of German science under Nazi rule. “German science presents a grim spectacle,” he wrote. “Grim for many reasons. First it became incompetent and then it was drawn into the maelstrom of depravity of which this country reeks—the smell of the concentration camps, the smell of violent death, torture and suffering.” German doctors were not practicing science, Alexander said, but “really depraved pseudoscientific criminality.” In addition to investigating crimes committed in the name of aviation medical research, Dr. Alexander was the lead investigator looking at crimes committed in the name of neuropsychiatry and neuropathology. In this capacity, he came face-to-face with the odious and core Nazi belief that had informed the practice of medicine under Hitler’s rule. Not only were all people not created equal in the eyes of the Third Reich, but some people were actually not humans at all. According to Nazi ideology, Untermenschen—subhumans, as they were called, a designation that included Jews, Gypsies, homosexuals, Poles, Slavs, Russian prisoners of war, the handicapped, the mentally ill, and others—were no different from white mice or lab rabbits whose bodies could thereby be experimented on to advance the Reich’s medical goals. “The subhuman is a biological creature, crafted by nature,” according to Heinrich Himmler, “which has hands, legs, eyes, and mouth, even the semblance of a brain. Nevertheless, this terrible creature is only a partial human being.… Not all of those who appear human are in fact so.” German citizens were asked to believe this pseudoscience; millions did not protest. German scientists and physicians used this racial policy to justify torturous medical experiments resulting in maiming and death. In the case of the handicapped and the mentally ill, the Untermenschen theory was used by German doctors and technicians to justify genocide.
As a war crimes investigator, Dr. Alexander was one of the first American servicemen to learn that the Reich had first sterilized and then euthanized nearly its entire population of mentally ill persons, including tens of thousands of children, under the Law for the Prevention of Genetically Diseased Offspring. All across southern Germany, one German physician after the next admitted to Dr. Alexander his knowledge of the child euthanasia program. This included Dr. Alexander’s own mentor and former professor, the neurologist Karl Kleist. During an interview in Frankfurt, Kleist confessed to Dr. Alexander that he had known of the policy of euthanasia, and he handed over military psychiatric reports that allowed him to circumvent personal responsibility and claim he was just following orders. Kleist was not arrested, but a few days later he was removed from his teaching job. The former teacher and student never spoke again, and it remains a mystery if Dr. Alexander requested that Kleist be fired. Within a few years Kleist’s name would appear on a secret Paperclip recruiting list. It is not known if he came to the United States.