Elizabeth Weise

USA TODAY

SAN FRANCISCO - A Pulitzer prize-winning computer security expert recently hired by the Chief Technology Officer of the United States, Megan Smith, has been denied a security clearance and is heading to the West coast.

Ashkan Soltani was previously the chief technologist at the Federal Trade Commission. He was hired by the White House’s Office of Science and Technology Policy as a senior adviser to Smith in December.

On Friday he posted to Twitter that he was disappointed to announce his departure as he had been notified last week that he would not receive the security clearance necessary to continue working at the White House.

"Bittersweet end to my stint in government," he tweeted.

In an interview with The Guardian, Soltani said that he didn't know why he had failed the check, but that he had passed the mandatory drug screening and the FBI background check was still underway.

There was "no allegation that it was based on my integrity or the quality of my work," he told the paper.

Soltani said his mandate had been to help Smith and her team "work though hard questions on consumer privacy, the ethics of big data and the recruitment of skilled technologists to government."

Soltani was on the team that won a Pulitzer Prize at The Washington Post for investigating surveillance initiatives of the National Security Agency.

He had researched and written about Edward Snowden, security, national policy and other issues at the Post, the Wall Street Journal and the New York Times. Many on Twitter speculated that his work about Snowden's leaks might have predisposed the security staff to distrust him.

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An official at the White House Office of Science and Technology Policy who was not authorized to speak on the record said Soltani was on a detail to the Office of Science and Technology Police from the Federal Trade Commission and that his detail had ended. The official was unable to comment further on an individual personnel matter.

At the White House, Smith has been trying to lure more computer technologists to come work for the government, despite lower pay and fewer perks than they can get in the white-hot tech job market. In multiple public appearances she has asked tech workers to consider serving their country by coming to work for it.

On Twitter, Soltani said he planned to move to the West coast.