White House fires Twitter critic

David Jackson | USA TODAY

Show Caption Hide Caption Who is the White House mole? A closer look at the notorious tweeter, who used @natsecwonk to hurl insults and expose information about the Obama administration.

President Obama's staff has unmasked and fired a national security official who tweeted critical comments under a pseudonym.

Jofi Joseph, tweeting under the handle @natsecwonk, once wrote: "I'm a fan of Obama, but his continuing reliance and dependence upon a vacuous cipher like Valerie Jarrett concerns me."

A federal law enforcement official, who was not authorized to commeny on the matter, told USA TODAY that Joseph is not under investigation, as has been reported

Other Obama staff members and officials — including Secretary of State John Kerry and former National Security adviser Tom Donilon — had also been targeted by @natsecwonk, which was shut down last week.

The secret Twitter feed also raised questions about the administration's handling of the 2012 attack on a U.S. facility in Benghazi, Libya.

The Daily Beast , which broke the story, reported that Joseph, who is well known in national security circles, "has also worked at the State Department and on Capitol Hill for Senators Bob Casey (D-Pa.) and (Vice President) Joe Biden. Until recently, he was part of the administration's team working on negotiations with Iran."

Of course, Joseph also insulted Republicans on his mystery Twitter feed: "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 .... "

Politico reported on the investigation into Joseph's Twitter activities:

"After a probe that included an investigation into Joseph's travel and shopping patterns — parsed from over 2,000 tweets — lawyers from the White House counsel's office confronted Joseph and ordered him to leave the executive complex, according to two sources familiar with the situation. Joseph had been scheduled to rotate out of White House duty to a senior job in the Pentagon, an administration official told Politico."

A federal law enforcement official, who was not authorized to comment on the matter, told USA TODAY that Joseph is not under investigation.