"Défago,Gérard (?-1942), Swiss entomologist working with Karl Roos on DDT. Both died, ages unknown, in an unexplained car crash near Heidelberg, Germany. The Swiss chemical company Geigy, which would eventually sell DDT to both sides in the war, had apparently sent them on a clandestine mission to inform the Nazi government of their research. The Germans hoped to use DDT against the potato beetle, which they apparently feared the Allies would employ as a weapon of biological warfare. One theory is that the visiting Swiss scientists learned something that day about Germany’s own plans for biological warfare."
https://strangebehaviors.wordpress.com/2011/01/14/the-wall-of-the-dead/