US government prosecutors accused NSA contractor of largest data theft in history

An undated handout photo shows the National Security Agency (NSA) headquarters building in Fort Meade, Maryland. (Photo by Reuters)

US government prosecutors say they would prosecute a former contractor for the National Security Agency (NSA) who is accused of stealing a "breathtaking" amount of classified information, the largest data theft the United States has ever seen.  

Federal prosecutors said on Thursday that Harold Thomas Martin spent over two decades stealing classified information from multiple government agencies.

The alleged criminal conduct "is breathtaking in its longevity and scale," prosecutors said, adding that the amount of stolen data is estimated to be at least fifty terabytes, enough to fill dozens of hard drives.

US Justice Department attorneys said they will bring charges against Martin that included violations of the Espionage Act, a move carrying far more severe penalties than previously announced charges.

A conviction under the Espionage Act can include prison time of up to 10 years on each count.

"The defendant knows, and, if no longer detained may have access to, a substantial amount of highly classified information, which he has flagrantly mishandled and could easily disseminate to others," Justice Department attorneys wrote in the 12-page filing.

Martin, 51, was arrested at his home in Glen Burnie, Maryland, in August and charged with felony theft of classified government material.

He was employed by Booz Allen Hamilton, the same consulting firm that employed NSA whistleblower Edward Snowden when he disclosed classified documents in 2013 that exposed NSA surveillance programs.

Officials said compared to Snowden's, however, Martin's theft is far greater. "The case against the defendant thus far is overwhelming," prosecutors wrote in the filing.

Martin is scheduled to appear in US District Court in Baltimore on Friday for a hearing. Prosecutors will ask the judge that Martin should not be released from jail on bail because he is a flight risk and a threat to national security and the physical safety of others.

The US Justice Department is also concerned that Martin may seek asylum from a foreign country, much in the way Snowden did from Russia. Snowden remains in Moscow as American authorities try to have him extradited.

The administration of US President Barack Obama has prosecuted more people, including Snowden, under the Espionage Act than all previous presidents combined.