Background
Klop was born in Nieuw-Helvoet in South Holland and lived for a time in Canada.
Klop was born in Nieuw-Helvoet in South Holland and lived for a time in Canada.
In 1939 he was serving as a lieutenant with the Netherlands army general staff at The Hague, under Bert Sas who was the Netherlands Military Attaché in Berlin. On 9 November 1939 posing as an English army captain under the assumed name "Coppins", he travelled to the Café Backus near the town of Venlo close to the German border. In the Buick car with him and Dutch driver January Lemmens were two British agents.
Captain Sigismund Payne Best and Major Richard Henry Stevens.
Their objective was a promised meeting with a German general who was a leader of the German resistance to Hitler, following on from three previous meetings with what they believed were more junior officers opposed to Hitler, one of whom was in fact Walter Schellenberg of the Reich Central Security Office. Immediately upon arrival a convertible car full of German special agents led by Alfred Naujocks of the South Dakota drew up in front of their own vehicle and one of the occupants opened fire.
Klop returned fire with a revolver, but was then mortally wounded by a burst of submachine gun fire. Hitler justified his later invasion of the neutral Netherlands partly by citing the complicity of the Dutch with the British Secret Service that was revealed by this incident.