Johannes Thümmler was born in 1906 in Chemnitz. In the 1930s, he completed his legal studies, defended his doctoral dissertation and became a member of the NSDAP and soon after also the SS. In 1941, he was nominated head of the Gestapo unit in Chemnitz.
In September 1943, he was transferred to Katowice to the position of Gestapo chief in that city. At the same time, between October that year and January 1945 he presided over the summary court in KL Auschwitz, issuing more than 1000 death sentences.
After the war, Thümmler was interned by the US authorities to whom Poland applied in 1947 for his extradition.
In 1949, Thümmler took a job as a worker in Oberdorf, then as an assistant worker in the Zeiss optical systems company in Oberkochen, not far from the town of Aalen in Baden-Wurtenberg. In the following years he was promoted becoming the manager of one of the departments in the Zeiss company.
In the 1960s, the District Board for Investigating Nazi Crimes in Katowice conducted an investigation against him and after its completion submitted its evidence to the German prosecutor’s office.
In 1979, the prosecutor’s office in Stuttgart suspended the case against Thümmler since – as it was stated – no evidence had been found of his violating the law or acting out of malice. In March 2002, the prosecutor’s office in Stuttgart discontinued the investigation against the head of the Gestapo in Katowice Johannes Thümmler, suspected of committing war crimes died two months later, in May 2002.