A National Security Agency contractor has been arrested and is being investigated for taking "highly classified" information, according to a statement by the Department of Justice.
The suspect, 51-year-old Harold Thomas Martin III of Glen Burnie, Maryland, was arrested in late August, the statement said, adding that he had a top secret national security clearance.
The statement did not specify the nature or quantity of the information taken, but spoke of six documents "obtained from sensitive intelligence and produced by a government agency in 2014."
After review, investigators found that the documents were classified as Top Secret, "meaning that unauthorized disclosure reasonably could be expected to cause exceptionally grave damage to the national security of the U.S."
The New York Times reported the contractor is suspected of stealing sensitive NSA source code meant to break into the computer systems of foreign governments such as Russia, China, Iran, and North Korea. It said he worked for the consulting organization Booz Allen Hamilton.
In a statement, Booz Allen Hamilton said that as soon as it learned of the arrest of one of its employees, "we immediately reached out to the authorities to offer our total cooperation in their investigation, and we fired the employee.
"We continue to cooperate fully with the government on its investigation into this serious matter," the company said.
The Justice Department did not mention what, if anything, the contractor may have done with the allegedly stolen information, which it said was found during a search at Martin's residence, including two storage sheds.
During the search, investigators found "hard-copy documents and digital information stored on various devices and removable digital media," the statement said. "In addition, investigators located property of the U.S. government with an aggregate value in excess of $1,000, which Martin allegedly stole."
If convicted, Martin faces a maximum of one year in prison for the unauthorized removal and retention of classified materials and ten years in prison for theft of government property, the Justice Department said.
"During the interview, Martin at first denied, and later when confronted with specific documents, admitted he took documents and digital files from his work assignment to his residence and vehicle that he knew were classified," the complaint said.
It is not clear how close the situation is to that of ex-NSA contractor Edward Snowden, who stole 1.5 million sensitive documents in 2013 and used them to leak details of several secret U.S. surveillance programs. The U.S. government filed espionage charges against Snowden, who would face 30 years in prison, if convicted. He has been granted asylum in Russia.