Karl Gröger (7 February 1918 - 1 July 1943) was a member of a Dutch resistance group executed in 1943. In 1943 the SS and police court sentenced him to death in Den Haag. In collaboration with a Dutch resistance group, he destroyed the registration of address office of Amsterdam, thereby destroying file cards of Dutch people which would have faced forced labour and deportation to concentration camps. He was given the title "Righteous Among the Nations" in 1986 by Yad Vashem.
Gröger was born in Vienna. He operated in the association of social democratic high school students. After that he studied medicine at the University of Vienna. Following his graduation in March 1938, Gröger fled to Amsterdam, where he continued his medicine study. Two years later, in May 1940, the German Wehrmacht marched into the Netherlands. He had to join the German Army. After some months the army kicked him out, because he was declared as partly Jewish. Unbeknownst to the Germans, Karl (Bubie as he was known to friends and family), was the product of a full Jewish mother - Frieda (who converted into the Catholic faith in 1911) and of a half-Jewish father - Karl Sr. Karl Jr. himself was baptized into the Catholic faith at birth.
Gröger joined the resistance movement of Gerrit van der Veen, a sculptor. Karl also worked for the underground newspaper "Rattenkruit" (rat poison) and took part in the assault against Amsterdam’s registration of address office on March 28. Gröger's resistance group broke into the building dressed up as policemen. They bemused the guards and blasted the building. Through this act, thousands of file cards of Dutch people who would have been deported to concentration camps were destroyed.
Afterwards, Gröger had to flee again. He hid himself at a farm but was discovered by the SS when he sent a message to his girlfriend. He was arrested by the Gestapo and was brought to the Amsterdam police jail. He was sentenced to death by the SS and police court in Den Haag in 1943. A mercy petition was refused by SS Reichsführer Heinrich Himmler. Thereon Gröger was shot by the police in the dunes near Overveen. Gröger told his lawyer that he hoped his actions would serve to establish a better relationship between the Netherlands and Germany.
Before his execution Gröger wrote in his farewell letter to his parents: "Lovely mother, lovely father. I will be killed tomorrow. I really had to act like this. I had no other choice. God gave me the power to put up with the situation. I prepared myself for death. Above all I refused to feel hate or revenge. I will be tough with the help of god and will die as a man if he wants." He also wrote "I believe that with this one action I brought more boon to humanity than an entire life as a physician would have done." (German: Ich glaube dass diese einzige Tat mehr Nutzen fur die Menscheit gebracht hat, als ein ganzes Leben als Arzt getan hätte).