Dr Johann Nelböck (1903–1954) was an Austrian former student of Moritz Schlick, the founder of the group of philosophers and scientists known as the Vienna Circle.

On June 22, 1936, Nelböck, who had already twice been committed to a psychiatric ward for threatening Schlick, shot him in the chest and killed him on the central staircase of the University of Vienna.

Although a German Protestant from minor Prussian nobility, Schlick was subsequently characterized in the press as a pivotal figure in disaffected Jewish circles, and the murder was applauded by Vienna's Nazis, immediately becoming a cause célèbre.

At Nelböck's trial for the murder of Schlick, besides some allegations of personal injuries, a significant part of his defence was the claim that Schlick's philosophical arguments had undermined his native moral restraints, a line of thought which Austrian Nazis, asserting Schlick's Jewish connections within the Vienna Circle, quickly developed and exploited, although not entirely without protest.

Nelböck was found guilty and sentenced to ten years' imprisonment, but was paroled after two. He became a member of the Austrian Nazi Party after the Anschluss (the unification of Germany with Austria) in 1938.

The victim

Moritz Schlick, the founder of the group of philosophers and scientists known
as the Vienna Circle.