By Mike Hellgren

BALTIMORE (WJZ) — Former NSA contractor Hal Martin pleaded not guilty Tuesday morning in a federal courtroom in downtown Baltimore to what is believed to be the largest theft of United States’ government documents in history.

Many of them were highly classified secret or top secret, and sources say they included the names of agents working abroad, putting their lives at risk.

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Martin’s attorney, public defender James Wyda, declined to comment on the case, despite repeated questions from WJZ.

Martin, wearing a striped inmate jumpsuit, told the judge he understood the charges against him. He asked for a trial by jury. Federal prosecutors estimate that trial could take three to four weeks.

He faces multiple counts of “willful retention of national defense information” that carry a maximum sentence of 200 years in prison and $5 million in fines.

United States Attorney for Maryland Rod Rosenstein told WJZ that Martin’s actions show how important it is to make sure those entrusted with high-level security clearances are following the law.

“The indictment alleges that for as long as two decades, Harold Martin flagrantly abused the trust placed in him by the government by stealing documents containing highly classified information,” Rosenstein said.

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The government alleges the thefts had taken place starting in 1996, ending last year during a raid on Martin’s home in Anne Arundel County.

Federal authorities say they found the equivalent of half a billion pages of stolen documents. Some were in an unlocked shed in his backyard in Glen Burnie, others were piled inside of his small house and in his car. Police also found several weapons.

There are questions about whether the government missed red flags, including a now-expunged charge that Martin impersonated a police officer, another charge of computer harassment, binge drinking and several concerning notes to colleagues.

Martin’s attorney said in a previous court hearing that his client was a hoarder who began compulsively taking documents and couldn’t stop. He said he didn’t do anything malicious, and there’s no proof Martin had any contact with a foreign government. Martin, a one-time Naval officer, worked for several government contractors, including the same one that employed Edward Snowden, who also once called Maryland home. The defense lawyer said Martin is “no Edward Snowden” and had no political or philosophical reasons for taking the documents.

Martin remains incarcerated. Federal authorities expressed concern he could be vulnerable to a foreign government if released pending trial. A grand jury formally indicted him last week. His wife has previously voiced support for him in court.

Martin is considered innocent until proven guilty.

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