A senior White House official who served on President Obama's National Security Staff has been fired for leaking internal information and insulting public officials on Twitter. Jofi Joseph, 40, was a director of nuclear non-proliferation at the White House and had been anonymously posting updates to the widely followed @NatSecWonk Twitter account since 2011. The Daily Beast first reported the firing on Tuesday, and a government official later confirmed the move to Reuters.

According to Politico, White House officials had been trying to unmask the Twitter user for months, ramping up efforts after he began using the site to raise questions about the administration's response to last year's Benghazi attacks. Investigators probed his travel, shopping, and tweeting records before finally confronting him last week, when the @NatSecWonk account suddenly disappeared without explanation. Joseph had been part of a team working on US negotiations with Iran, and had been scheduled to move on to the Pentagon as part of a regular staff rotation, sources tell Politico.

"I deeply regret violating the trust and confidence placed in me."

"It has been a privilege to serve in this Administration and I deeply regret violating the trust and confidence placed in me," Joseph said in an email to Politico Tuesday. "What started out as an intended parody account of DC culture developed over time into a series of inappropriate and mean-spirited comments.  I bear complete responsibility for this affair and I sincerely apologize to everyone I insulted."

Joseph used the @NatSecWonk account to post sarcastic and often insulting observations about a wide swath of political leaders, including Vice President Joe Biden and former Secretary of State Hillary Clinton. The account was widely followed among Washington insiders, and it attacked both Democrats and Republicans alike.

"So when will someone do us the favor of getting rid of Sarah Palin and the rest of her white trash family? What utter useless garbage .... ," Joseph tweeted last year. He also criticized the appearance and weight of female political figures like Liz Cheney and Ann Romney, and once questioned Senator Lindsay Graham's (R-SC) sexuality.

According to Politico, there are suspicions that Joseph may have been behind a second anonymous Twitter account, @dchobbyist, that publicized more lurid details about Washington, DC escort services and political sex lives. Joseph declined to comment on the second account, which as of this writing, remains active but private.