A former contractor with the National Security Agency arrested in August 2016 will plead guilty this month to one of the 20 counts he faces.

Harold Martin III, 52, will plead guilty on Jan. 22 to one count of willful retention of national defense information, according to The New York Times.

He faces up to 10 years in prison, three years of supervised release and fines of up to $250,000 for that charge, according to Nextgov.

Federal authorities have stated that Martin removed classified information from the agencies he worked for and stored those documents in his Maryland home for decades. Some of the documents were classified as top secret and sensitive compartmented information.

Martin’s attorneys describe him as a “compulsive hoarder,” the Times reported. He began taking home highly classified documents from the National Security Agency and other government agencies in the late 1990s. They were in paper form, as well as on hard drives and flash drives in his Glen Burnie, Maryland home; in a shed in his yard; and in his car. In all, he stole 50 terabytes of data, and his activity “went undetected until his arrest on Aug. 27, 2016.”

Among the cache of information he took were NSA hacking tools. Those tools wound up available for purchase on the internet.

There is no deal on the table for Martin, and although he has pleaded to this solitary charge, he won’t be sentenced until all of the remaining counts are resolved, Nextgov reported.

A schedule laid out by Judge Marvin J. Garbis of United States District Court lists additional dates for continuing legal action regarding the other 19 charges Martin still faces, the Times reported.

This is an interesting case to watch, because the amount of documents Martin took outnumbers that of Edward Snowden, perhaps the most security clearance-related case in the past few years, said Catie Young, a security clearance lawyer.

Snowden was a contractor who stole hundreds of thousands of secret documents and gave them to journalists.

When it’s time for Martin to be sentenced, his attorneys plan to argue for leniency “on the grounds that he suffers from a mental disorder that caused him to take the material home year after year; that he never tried to give it to the news media, a foreign country or anyone else; and that he is a Navy veteran and a patriot who served his country for years,” the Times reported.