I kind of wanted to say Sewell but I wasn't sure I remembered the name right and I guess I was too lazy to look it up---but that's the one. Sewell is a big advocate of this theory but I think most people, even conspiratorial ones, think of him as kind of a crank. I haven't read the book so I won't judge too harshly, I just know that the rogue nuclear mission theory sort of hinges on a lot of political currents within the Kremlin and KGB that aren't in evidence elsewhere.