The Daily Beast reported Tuesday night that Jofi Joseph, a nonproliferation expert at the National Security Council, was fired last week.
Joseph did not respond to requests for comment. A White House official, speaking on the condition of anonymity because the matter involves a personnel matter, said only that Joseph no longer works there.
The Twitter feed @natsecwonk, a guilty pleasure among national security analysts, reporters and others, disappeared last week. Searches for it Tuesday on Twitter yielded messages that there was no such user.
The Twitter feed had rankled Obama administration officials and career State Department higher-ups, some of whom suspected that @natsecwonk was a current or former department official.
The feed ran for more than two years. The posts appeared often, but not daily. Some were flippant comments about news stories or analyses done by Washington’s large foreign policy commentariat. Others were musings on the policy workings of the administration.
The administration had recently tried to track the source of the anonymous tweets, a current and a former official said, but it was not clear whether that effort led to @natsecwonk’s unmasking.
The posts never included classified or highly sensitive information, making a true leak investigation difficult to mount, but they often contained insider details.
The level of detail led to speculation that the poster was a Hill staffer with access to White House briefings, but also may have raised suspicion that the tweets were coming from within the White House.