| ® || The Crime Scene Investigation | 139 puter intended to be used for temporary storage by authorized ser- vice personnel. Finally, the data was transferred off this auxiliary computer presumably to thumb drives or other external storage devices. This download occurred just days before Snowden left the NSA on May 17, 2013, having told the agency that he needed a med- ical leave of absence. The quantity of stolen documents, 1.7 million, does not necessar- ily reveal the damage and can itself be misleading. Many documents do not reveal current or known sources or methods, and others may have little value to an enemy. And a large portion of the documents might have been duplications. The quality of some of these docu- ments is another matter. Just one document that exposed a source or method of which enemies are unaware can be of immense value. One such document taken by Snowden provided what Ledgett called “a roadmap” to the NSA’s current secret operations, revealing to an adversary such as Russia, China, or Iran “what we know, what we don’t know, and, implicitly, a way to protect themselves.” There were many documents in the Snowden breach that met these criteria, © according to a national security official at the Obama White House. re) General Alexander closely followed the investigation as it devel- oped over the summer of 2013. By then, of course, the whole world knew that Snowden had stolen a vast trove of NSA documents. Alexander saw major inconsistencies developing between Snowden’s personal account of the theft and what had actually happened. The timeline established by the government’s investigators did not match Snowden’s story line. “Something is not right,” Alexander said in an interview. For one thing, Snowden had made the claim to journalists, four months after he was in Russia, that he had turned over all the documents he took from the NSA’s compartments to Poitras and Greenwald in Hong Kong. On August 18, the investigators had the opportu