The anonymous @NatSecWonk Twitter account had been the subject of Capitol Hill gossip for years, but after the account turned mean-spirited, the account became the target of some serious counterintelligence work. A new Washington Post report claims cabinet officials turned to classic anti-mole techniques to ferret out @NatSecWonk's true identity, spreading misinformation to different sources and seeing which of it popped up on the telltale Twitter feed. This week, the perpetrator was revealed, a member of the White House's Iran negotiations team named Jofi Joseph. "I sincerely apologize to everyone I insulted," Joseph said in a statement on Wednesday.

The account was particularly controversial because of the strange position Twitter occupies in modern Washington. Staffers are forbidden from using Twitter inside the National Security Council building and their government-issue phones don't have web access, so insiders speculate Joseph must have been tweeting from his personal phone while outside the building. Still, many in the administration were shocked to find the anonymous Tweeter so close. As one official told the Post, "it was like they were hunting for bin Laden in a cave and he was right in the belly of the beast all along."