I want to know the answer to the following question:
Feynman borrowed a car from Klaus Fuchs, who was later found to be a what?
All the background I'm provided with is that "He left a series of notes in the cabinets as a prank, which initially spooked his colleague, Frederic de Hoffmann, into thinking a spy or saboteur had gained access to atomic bomb secrets.". Is that enough to answer the question?