Karl Gähner was born in 1910 into a large family in Aplerbeck. He had three brothers and two sisters. Together with his parents and siblings, he moved to Holzwickeder Str. 27 in 1923.

Karl is presumed to have worked as a coalminer, like his brothers and father.

Politically, the whole Gähner family were supporters of the Social Democrats. Karl and his brothers are also reported to have joined the “Reichsbanner”, an organization closely affiliated to the Social Democrats which was formed in the 1920s and sought to combat both Right-wing violence and the radical policies of the KPD, the German Communist Party.

Karl Gähner was detained in summer 1943, first of all in Steinwache police station and then in the Gestapo building in Hörde after being denounced by a work colleague for expressing negative views about the Nazi regime, the talk of the “final victory” and the treatment of prisoners of war.
He appears to have been subjected to massive mistreatment both at the Steinwache and in Hörde.

In April 1944, finally, Karl was found guilty by the Volksgerichtshof, the so-called “People’s Court” in Berlin, of “subversion of the national defence capability”, and sentenced to death. After all pleas for clemency were refused, he was beheaded a month after sentence was passed.