The FBI recently arrested a National Security Agency contractor on suspicions that he stole highly classified computer codes used to hack into foreign government networks, senior intelligence officials told the New York Times on Wednesday.
Disclosure of the stolen documents would "cause exceptionally grave damage to the national security of the U.S.," the Justice Department said in a statement detailing the federal criminal complaint filed against Maryland resident Harold Thomas Martin.
Martin, 51, was charged with theft of government property and unauthorized removal and retention of classified materials by a government employee or contractor.
FBI agents raided his home in August, where they recovered documents and electronic devices that contained classified information. Many of the seized materials bore "top secret" markings.
Martin worked for the consulting firm Booz Allen Hamilton, the same company that Edward Snowden was contracting with in 2013 when he leaked a trove of stolen documents to journalists exposing the NSA’s surveillance programs. If Martin is convicted, the incident would mark the second time in three years that an insider was able to steal highly classified documents from the NSA.
Martin appeared in court on Aug. 29. He initially denied taking the materials during an interview with the FBI. He later told agents "he knew what he had done was wrong and that he should not have done it because he knew it was unauthorized," according to the complaint.
Martin is suspected of stealing top secret "source code" developed by the NSA to break into the networks of U.S. adversaries including Russia, China, Iran, and North Korea, according to the New York Times.
Lawyers for Martin said there is no evidence that he "intended to betray his country."