The head of the British Secret Intelligence Service, Stewart Menzies, stated that Cicero was indeed a double agent and that among the documents submitted to the Germans were documents of misinformation. Author James Srodes states in his biography of Allen Dulles that some British historians believed that Cicero was "'turned' into a double agent to send disinformation via von Papen". Malcolm Gladwell, author of "Pandora's Briefcase", said that an interviewer had questioned Menzies before he died about whether he was telling the truth. Menzies told the interviewer, "Of course, Cicero was under our control," but his truthfulness is questioned. Gladwell stated in an article in "The New Yorker", "If you had been the wartime head of M.I.6, giving an interview shortly before your death, you probably would say that Cicero was one of yours." Gladwell also mentions that while Ribbentrop was wary of Bazna, which curtailed the dissemination of some of Bazna's intelligence, most German intelligence officials were not wary of him.