A former employee with the National Security Agency (NSA) on Thursday pleaded guilty to stealing massive quantities of classified materials from his workplace.
Reuters and NPR report that Harold Martin, 54, pleaded guilty to stealing classified documents as part of a plea agreement following his indictment last year on 20 counts related to 50 terabytes worth of stolen NSA files prosecutors said he was hoarding at his house.
The Baltimore man's lawyers argued that his actions constituted those of someone who was mentally ill and was trying to take work home with him, not an attempt at treason.
Still, the scale of his document trove indicated that the theft could represent the greatest illegal attainment of classified information in U.S. history.
“His actions were the product of mental illness. Not treason,” his attorneys told Reuters.
Sentencing in Martin's case is set for July 19. If a judge agrees to his plea agreement, Martin could face nearly nine years in prison.
"The American people entrusted Harold Martin with some of the nation's most sensitive classified secrets," Assistant Attorney General John Demers said, according to NPR. "In turn, Martin owed them a duty to safeguard this information."
Martin's arrest occurred in 2016, and at the time the Justice Department claimed that his documents related to a wide range of national security issues.
“These documents were produced through sensitive government sources, methods and capabilities, which are critical to a wide variety of national security issues," the Justice Department said at the time. "The disclosure of the documents would reveal those sensitive sources, methods and capabilities."