The CIA never revealed who spirited the documents out of Iran or how. However, former senior German Foreign Office official Karsten Voigt explained to this reporter in 2013 that the German intelligence agency, the BND, had been furnished with the collection by an occasional source whom the intel chiefs considered less than credible.
And who was this source? According to Voigt, he belonged to the Mujahedeen e-Khalq (MEK), the exile Iranian cult which had fought for Saddam’s Iraqi forces against Iran during the eight-year war and by the early 1990s was passing information and propaganda that Mossad did not want to have attributed to itself.