Arrest and investigation
An investigation into Tesch started after a former Testa bookkeeper, Emil Sehm, wrote to British military authorities, who were present in Hamburg since the city was in the British military government's zone of Allied-occupied Germany. Sehm said that in 1942, he had come across one of Tesch's travel reports. In it, Tesch had recorded an interview with leading members of the Wehrmacht, during which he was told that the burial, after shooting, of Jews in increasing numbers was proving increasingly unhygienic, and that it was proposed to kill them with prussic acid. Allegedly, when Tesch was asked for his views, he had proposed to use the same method, involving the release of prussic acid gas in an enclosed space, as was to exterminate vermin. He had then trained the SS to use Zyklon B to kill human beings.
Sehm said he copied this report and showed it to a close friend, Wilhelm Pook. Pook advised Sehm to destroy the letter immediately since keeping the letter posed a safety risk. Sehm destroyed the letter. He was fired for unknown reasons after the firm's building suffered an air raid in July 1943.
Tesch was detained in September 1945. British officers Walter Freud and Fred Pelican were assigned to the case.[4] The day after Tesch's arrest, Sehm accompanied the British to the firm building, only to find that registry had seemingly been destroyed in an air raid (it was later suspected that the registry had been intentionally destroyed).[5]
During questioning, Tesch presented himself as a respectable businessman and chemist. He denied all suggestions and accusations that he had collaborated with the SS regarding the extermination of Jews. He said he never attended a conference discussing the subject, had not devised any methods for using Zyklon B other than fumigating the barracks, and had not known that the gas was being used to kill people. Tesch said he did not even know the gas was being sent to concentration camps.[4]
Tesch admitted to being a member of the Nazi Party and a "supporting member of the SS". He explained that he had been affiliated with the SS Hygiene Institute to obtain their business. Freud did not believe Tesch, but had no evidence beyond Sehm's word. At the same time, Freud was facing pressure from high command to release Tesch, since British occupation forces were using Zyklon B to fumigate their ships. Against the wishes of Freud and Pelican, Tesch was released on 1 October 1945.[4]
Both men immediately started lobbying their superiors to let them continue their investigation. Freud, who was a chemist himself, was adamant that the investigation be allowed to continue. He and Pelican told high command that Tesch's case was the first time they were dealing "not with people directly concerned in the murder or ill-treatment of prisoners or slave workers, but with those who lent their skill and services to facilitating the gruesome work of the concentration camps and so identified themselves with breaches of the laws of war on a wholesale scale."[4] Their superiors relented, and Tesch was re-arrested on 6 October 1945. Freud and Pelican started searching through other files, and found that the firm had a sharp rise in profits in 1942 and 1943, when the mass gassings were at their peak. However, they could not find anything suggesting that Tesch or his employees knew their product was being used to kill people. Raids of the firm's employees turned up nothing.[4]
During further questioning, Freud reported that Tesch adopted an attitude of ignorance carried "to an absurdity." The questioning of Tesch's deputy executive, Karl Weinbacher, also failed to get any answers. Freud reported that Weinbacher was "blindly obedient, has a slow brain", and was "an arrogant man with limited intellect." Freud said Weinbacher "was so insolent that special steps had to be taken by the interrogating officer."[4]
The British administration was soon insisting that the firm needed to resume its fumigating. The firm's accountant, Alfred Zaun, was asked to substitute for Tesch. He agreed, but said he needed written authorisation from Tesch. Freud and Pelican, becoming desperate, organised a meeting with hidden microphones, hoping that Tesch might incriminate himself. However, he and Zaun whispered to each other quietly enough that the microphones did not pick up anything.[4]
After the meeting, Zaun was interrogated. Officials told him the room was bugged and bluffed that they had overheard everything. Zaun panicked and admitted that the firm had sold Zyklon B to concentration camps. He said he had records to prove the sales, but claimed he did not know their purpose. While searching through the new documents, Freud came across some other documents discussing a "training course" delivered by Tesch to SS personnel at Sachsenhausen in January 1941. The names of several SS men were listed. All of them were low-ranking.[4]
One name drew Pelican's attention: Wilhelm Bahr. Bahr, a medical officer, had earlier been identified by a survivor of the Neuengamme concentration camp as having participated in the murders of hundreds of prisoners. After the war, Bahr had gone into hiding in the cellar of a home near the Neuengamme camp. His plan was to wait until the British had occupied the town, wait a few more weeks, then leave the cellar and return to his old life. However, Bahr was caught after someone noticed him scavenging for food and alerted British authorities. In May 1946, a British military court found him guilty of war crimes and sentenced him to death for actively participating in mass murder. Bahr was executed in October 1946.[4]
At this point in time, however, Bahr was still alive and in custody. When British officials asked Bahr to talk about what he did in Neuengamme, he immediately confessed. At the camp hospital, Bahr said he had murdered Jews and other "subhumans" using phenol injections. Those deemed unfit for work were injected with the deadly mixture. Bahr insisted to a horrified Pelican that the victims were killed "painlessly and humanely", and had all died within minutes. He said he had killed 90 to 100 inmates this way on a daily basis in Neuengamme, and that overall, he had likely killed over 1000 people.[4]
In 1942, Bahr said he was given a training course on the use of Zyklon B by Tesch. He was certified and shown how to use Zyklon B for delousing. Bahr said he usually just used the gas for its original purpose, disinfection. However, on one occasion, he had been ordered to empty tins of Zyklon B into a sealed barracks filled with approximately 200 Soviet POWs. Bahr said that Tesch had not taught him the procedure he employed to use Zyklon B on people.[4]
Although the evidence against Tesch was circumstantial, Freud was unwilling to drop the case. Tesch, Weinbacher and Joachim Drosihn, the firm's first gassing technician, were indicted for war crimes. The charge was that the defendants, "between 1st January, 1941, and 31st March, 1945, in violation of the laws and usages of war did supply poison gas used for the extermination of Allied nationals interned in concentration camps, well knowing that the said gas was to be so used."[3]
