BALTIMORE, Oct. 20 (UPI) -- Federal prosecutors said Thursday that a former contractor for the National Security Agency stole a "breathtaking" amount of classified information over a period of 20 years -- the largest data heist the United States has ever seen.
Prosecutors laid out their case against Harold T. Martin III in Baltimore on Thursday, in a court filing that accuses the former contractor and Navy veteran of repeatedly violating federal espionage laws by removing the materials and amassing a personal archive.
"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.
Prosecutors say Martin made off with "an astonishing quantity" of top secret data -- that comprised 50 terabytes of digital information and "six full banker's boxes worth of documents."
Government attorneys said some of those highly classified materials were not kept in secure locations, either. Investigators said they found some of it lying around in his home office and some in his vehicle.
Martin is scheduled to appear in U.S. District Court in Baltimore on Friday for a hearing. Justice officials are expected to ask that bail be revoked because they're afraid he might disseminate some of the materials if he's released pending trial.
The Department of Justice is also concerned that a foreign nation might offer him asylum -- much in the way Russia did for Edward Snowden, another former NSA contractor accused of stealing top secret information. He remains in Moscow as U.S. authorities try to have him extradited.
Officials said compared to Snowden's, however, Martin's theft is far greater.
If convicted of violating federal espionage laws, Martin could be sent to prison for 10 years on each count.
"The case against the defendant thus far is overwhelming," prosecutors wrote in Thursday's filing.
Martin's attorneys argued in their own filing that the 51-year-old Maryland resident is not a flight risk and that he should be allowed to remain free under court supervision.
"The government concocts fantastical scenarios in which Mr. Martin -- who, by the government's own admission, does not possess a valid passport -- would attempt to flee the country," public defenders James Wyda and Deborah Boardman wrote.
Prosecutors have not found evidence to indicate Martin may have given the secret materials to anyone.
"There is no evidence he intended to betray his country," they added. "The government simply does not meet its burden of showing that no conditions of release would reasonably assure Mr. Martin's future appearance in court."