A man previously employed by the National Security Agency pleaded guilty Friday for illegally taking classified information from the agency’s office.

Nghia Pho was employed starting in 2006 by the NSA as a Tailored Access Operations developer, according to the Justice Department. He pleaded guilty on one count of willful retention of national defense information.

Authorities discovered classified documents, some in digital form, in his Maryland home that were retrieved from the agency between 2010 and 2015.

As part of his job, Pho worked on highly classified, specialized projects and had various security clearances, according to the Justice Department. Some of the documents and writings he obtained included information about national defense that was classified as Top Secret and Sensitive Compartmented Information.

The New York Times reported that Pho was the NSA employee that was targeted by Russian intelligence hackers that hacked NSA tools through Kaspersky Lab software, a top Russian software company. Pho had Kaspersky Lab antivirus software on his personal computer.

It’s unclear whether Kaspersky Lab employees, who have refuted working on behalf of Russian intelligence, were aware that the documents had been stolen, although the group admitted NSA hacking software was found on a customer’s computer. They said the software was removed and destroyed.

Pho will be sentenced on April 6, 2018, when he could face up to 10 years in prison.

Two other NSA employees have been arrested for gathering classified info since October 2016.