Updated

A former National Security Agency contractor was indicted by a federal grand jury Wednesday on charges that he stole reams of highly classified documents.

Harold Martin, 52, was charged with 20 criminal counts of  willful retention of national defense information.

Prosecutors allege that between 1996 and 2016, Martin stole top secret documents from the NSA and several other agencies and kept them in his Glen Burnie, Md. home and car.

"The FBI investigation and this indictment reveal a broken trust from a security clearance holder," Gordon Johnson, special agent in charge of the FBI's Baltimore field office, said in a statement.

Prosecutors had previously accused Martin of a "breathtaking" theft, and had raised the potential that he could be providing the information to a foreign government. However, the indictment contains no allegations that he spied for or colluded with any other country or even that he gave away the documents.

Martin's attorney, federal defender James Wyda, has previously described his client as a "compulsive hoarder" who never intended to harm his country and who took work documents home with him as he strove to be as committed to his job as possible.

The documents included sensitive NSA briefings and reports, including a 2009 draft of a signals intelligence directive that outlined methods and procedures for protecting the U.S. and a 2014 report containing information on foreign cyber intrusion techniques.

Martin is also accused of stealing a CIA document detailing foreign intelligence collection sources and methods; a National Reconnaissance Office document that had information about the launch of an intelligence collection satellite; and an NSA document with information on planning and operations concerning suspected terrorists.

Martin, a former U.S. Navy lieutenant, has been in custody since the FBI arrested him in August.

Martin is a former employee of Booz Allen Hamilton, a contractor which also employed NSA leaker Edward Snowden. Snowden fled to Moscow in 2013 after revealing details of the agency's surveillance operations.

If convicted, Martin faces up to 10 years in prison for each count. He is due to appear in court Feb. 14.

The Associated Press contributed to this report.