NSA Contractor Who Allegedly Stole Top Secret Info 'More Weirdo Than Whistleblower,' Officials Say

— -- The National Security Agency contractor who federal authorities say took top secret information from the NSA is being described as "more weirdo than whistleblower," senior officials told ABC News.

Harold Martin, 51, was arrested in late August in what neighbors described as a dramatic FBI raid, but it was not until Wednesday that his curious case was revealed in a criminal complaint. In court documents, the FBI says Martin took home physical documents and information stored on digital devices, some of which was sensitive compartmented information (SCI), the highest level of classification.

It was information that the FBI said, if made public, would "reasonably be expected to to cause exceptionally grave damage to the national security of the United States." In all, the Department of Justice said investigators seized "thousands of pages of documents and dozens of computer or other digital storage devices and media" that held "many terabytes of information."

Although Martin worked at Booz Allen Hamilton, the same contractor for whom Edward Snowden worked, and was apparently able to slip through the NSA's security with highly sensitive information, as Snowden did in 2013, officials said overnight that that appears to be where the similarities between the two end.

It is unclear why Martin, a Navy veteran, allegedly removed so much sensitive information from his workplace and allegedly stored it in his home, nearby woodsheds or his vehicle, but he has not been charged with espionage — indicating to some former officials that this case may not be as serious as Snowden's. The Department of Justice said Tuesday that if convicted, Martin could face up to 11 years in prison — one year for unauthorized removal of classified material and 10 years for theft of government property. Snowden, however, could face a far harsher prison sentence, should he return to the U.S. from Moscow; the U.S. government has said the death penalty will not be sought.

"It's not a repeat of Snowden, but it is another insider," Chris Inglis, a former NSA deputy director, told ABC News Wednesday. "It could be quite harmful, but [so far] it's not as malicious or nefarious."

Jim Wyda, a public defender assigned to Martin, said there is "no evidence Hal Martin intended to betray his country."

"What we do know is that Hal Martin loves his family and his country. He served our nation honorably in the United States Navy, and he has devoted his entire career to serving and protecting America. We look forward to defending Hal Martin in court," Wyda said.

Regardless of Martin's intentions, the incident is another embarrassment for the NSA, coming three years after Snowden made off with a cache of data that exposed dozens of NSA surveillance programs. It is unclear whether Martin purportedly absconded with his data before or after post-Snowden security reforms were put in place.

"When you download this kind of top secret information off the NSA network into your own computer or into a thumb drive, alarms should go off. Apparently they didn't," said former White House cybersecurity adviser and current ABC News consultant Richard Clarke.

Martin's former employer, Booz Allen, released a statement Wednesday saying the company fired one of its employees, without identifying Martin, after learning of his arrest and that the firm continues to work with law enforcement.

The federal complaint complaint says Martin was interviewed by federal agents in late August and, 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." He allegedly said he knew what he had done was wrong.