The FBI busted an NSA contractor after finding top secret documents hidden in his home and car. His arrest was kept secret for more than a month.
Investigators searched the Maryland home of Harold Thomas Martin III on August 27 and found several documents, both digital and physical, stashed on multiple devices. "A large percentage" of the stolen information was labeled top secret, according to the Department of Justice.
Among the classified documents discovered in the FBI's search, six contained highly sensitive information that would have revealed the US government's sources, methods and capabilities, investigators said.
The secret files, if leaked, could have caused "exceptionally grave damage" to the US' national security, DOJ officials said. The theft highlights the challenge of locking down sensitive information at all organizations, whether it's a small company protecting credit card numbers or a US spy agency trying to keep its secrets.
Martin, 51, is suspected of stealing the NSA's source code used to break into computer networks in nations like Russia, China, Iran and North Korea, according to The New York Times. The code might have been outdated, sources told the newspaper.
Martin was a contractor for Booz Allen Hamilton, the same consulting firm that NSA whistle-blower Edward Snowden worked for. Snowden revealed the NSA's massive surveillance programs after leaking a stash of the agency's files and data to journalists in 2013.
Booz Allen said it fired Martin immediately after learning of his arrest and that it's cooperating with authorities as they investigate. It also said Martin's actions don't reflect the company's core values.
Booz Allen has a large presence at US intelligence agencies. The company has a workforce of about 22,600, and 69 percent of its workers hold security clearances with US intelligence agencies, according to company tax filings. Booz Allen generated $1.3 billion in revenue from contracts with US intelligence agencies, including the NSA, in the fiscal year ending in March 2016.
"Our employees continue to support critical client missions with dedication and excellence each day," Booz Allen said in a statement.
Snowden commented on Martin's arrest via Twitter, pointing out that his own situation was much different from Martin's.
"Am I correct in reading they didn't charge him under the Espionage Act? Under this administration, that's a noteworthy absence," tweeted Snowden, who faces charges under the act. Snowden is correct: the FBI omitted any charges against Martin under the act.
It's unclear if Martin gave third parties any of the information he's charged with taking.
The FBI charged Martin on August 29, but the arrest complaint had been sealed until October 5. If convicted, Martin faces more than 10 years in prison. He was charged with the unauthorized removal and retention of classified materials, and theft of government property, none of which falls under the Espionage Act.
First published October 5, 11:21 a.m. PT.
Update, 11:56, 12:43 p.m.: Adds comment from Booz Allen Hamilton and details about the company's operations.
CNET Reporter Laura Hautala contributed to this report.