As I said in my last post, resisters needed to know why their colleagues were arrested in order to know if they themselves were in danger. If the resisters knew that their colleague had been arrested for the illegal work they were all doing together, then they wanted to know how the police found their colleague.

With that information they would have a better idea of the extent of the danger and what they could do about it. It was hard, though, to know, and speculation abounded. In the case of the sweeping arrests of Dutch-Paris agents in February, 1944, no one knew for sure how the police found them, but many people had theories.

The Dutch intelligence services in Madrid, for example, suggested that Weidner’s sister had been arrested because a French courier was arrested shortly after taking microfilms to her. Indeed, after the war the Frenchman was convicted of betraying a number of his resistance colleagues. But whether he gave her name under torture or not, the German police did not find her through him. She was arrested because a Dutch-Paris courier had written her name in a notebook.

One of her colleagues who was also arrested and deported to the concentration camps was convinced that a Dutchman in the group had betrayed them all. He remained convinced of that betrayal long after Weidner had shown him the confession of the woman who gave the Germans his address after they tortured her.
American aviators hiding in a Dutch-Paris safe house decided that they had been betrayed by a man they thought was a Polish aviator because he went on a lot of walks and was not arrested with them. As it turned out, the man was Dutch and had been escorted to Paris the night before rather than a German agent provocateur.

All of these theories were wrong, but they served the purpose of making sense of a bad situation for the people trapped in it. Fortunately, Weidner and the other Dutch-Paris leaders still at large were able to figure out what had happened in February within a few weeks and warn those in danger to go into hiding.