The Dutch Nazi spy Nolly (Geesje Koopmans) was responsible for leading them to the Beje and ten Boon families but her actual motive in the betrayal has since been the subject of conspiracy theories. However, it seems as though Nolly may very well have had no motivation other than her Nazi sympathies and possibly financial incentives, while some theories of revenge seem unlikely given the relative anonymity within which the entire Dutch underground and Resistance movements in general had to function.