Like detectives, historians try never to rely on only one witness to an event. Everyone sees things from their own perspective, and very few people ever have all the information. So we look for as many documents as possible and piece together the story as best we can. In the case of Dutch-Paris, the documents are scattered across dozens of archives, in large part because the witnesses came from many lands. Here’s an example.

When the Germans raided a Dutch-Paris safe house in Brussels in February 1944, they captured ten Allied airmen. But there had been an eleventh military fugitive in the boarding house the night before. Why wasn’t he lined up along the garden wall with the others?

The Americans thought the eleventh man was a traitor or a German agent pretending to be a Pole. They distrusted him, possibly because he went on a lot of walks. The fact that he wasn’t captured with them confirmed their suspicions. This is an entirely plausible scenario and fits into the limited information available to the Americans. German agents certainly did infiltrate escape lines, although they usually took them all the way to England rather than betraying them in Brussels. I learned about the American explanation for the arrests from the navigator of a B-17 who was there and generously shared his recollections with me via email.

In the British archives, however, I found a report filed in May 1945 by a New Zealander who flew for the RAF and described his capture after his return from a POW camp. According to him, the eleventh man was a Dutch officer who had been taken to Paris the previous evening. This story also makes sense. Dutch-Paris did take many Dutchmen as well as aviators to Spain, and they did tend to separate the two groups when traveling between cities. Also, the resisters would have been much more likely to let a Dutch officer walk around Brussels than an American or New Zealander. Any Dutchman understood the realities of occupation and how to stay out of danger better than an American.

So now we have two theories about the eleventh man: he was a traitor or a Dutch officer who had left for Paris. None of the resisters captured in the same raid as the aviators had anything to say about any of the eleven fugitives in their postwar reports. The mystery seems unsolvable, except that in an archive in the United States and two archives in France, there are reports written by a Frenchwoman about her own arrest in Paris on March 23.

According to this Frenchwoman, she had been sheltering a Dutch captain, an instructor at the flight school, who kept going out for walks and to meet with acquaintances among the Dutch colony in Paris. The Gestapo raided her apartment looking for him. She saw him later that afternoon at Gestapo HQ in the company of another Dutch-Paris agent, without knowing how they came to be in the same police car. That’s something we’re unlikely to ever know as both parties died in the concentration camps. The Frenchwoman knew almost nothing about the Captain, who spoke little French. She had first met him on 13 March. There is no reason to think that the New Zealander’s Dutch army captain and the Frenchwoman’s Dutch pilot-captain are the same.

Except that there are some postwar reports written in Dutch and French in an archive in the US. In one of those, a Dutch-Paris agent lists the names of some of the people he guided between Brussels and Paris. And for 27 February, he lists the name of the Dutch captain captured in Paris on March 23.

So the eleventh man was a Dutch captain who had left for Paris the night before the arrests. Did he betray the safe house in Brussels? No. I know that because in the Dutch national archive and in an American archive there are copies of a signed declaration taken in October 1945 in which a Dutch-Paris agent admits that she gave the Germans the address of the safe house after they had tortured her in Paris on 18 February 1944. The Germans executed coordinated raids on all the addresses she admitted to giving them on 26 and 28 February, thus confirming the agent’s statement.

So the mystery of the eleventh man is solved, but it took three languages and twice as many archives to do it.