Sigurdur Siggi" Thordarson, [is a] cherubic, blond 21-year-old who has been called everything in the [Icelandic] press from "attention seeker" to "traitor" to "psychopath". Four years ago, just as WikiLeaks was winning international notoriety, the then-17-year-old hacking prodigy became Assange's youngest and most trusted sidekick. But as Assange became more embattled and besieged, the protg turned on his mentor in the most shocking of ways: becoming the first FBI informant inside the group. His tale reveals not only the paranoia and strife within WikiLeaks, but just how far the feds were willing to go to get Assange. The revelation of Siggi's role as an FBI snitch has polarized WikiLeaks insiders. WikiLeaks spokesman Kristinn Hrafnsson [dismissed] Siggi as "a pathological liar." While other WikiLeaks insiders also question Siggi's credibility, they insist that his story can't be discounted, and there's more to it than the organization is letting on. The truth, it seems, may be held in the leaks. Siggi has provided Rolling Stone with more than a terabyte of secret files he claims to have taken from WikiLeaks before he left in November 2011 and gave to the FBI: thousands of pages of chat logs, videos, tapped phone calls, government documents and more than a few bombshells from the organization's most heated years. Whatever their origins, the SiggiLeaks are a deep and revealing portal into one of the most guarded and influential organizations of the 21st century - and the extreme measures its embattled leader is willing to take.