The FBI on Thursday arrested a man who allegedly leaked hundreds of classified Pentagon documents, Attorney General Merrick Garland said in a press briefing.

Jack Teixeira, 21, a member of the Massachusetts Air National Guard, was taken into custody “without incident” at his home, Garland said.

“Today, the Justice Department arrested Jack Douglas Teixeira in connection with an investigation into alleged unauthorized removal, retention, and transmission of classified national defense information,” Garland said, declining to answer questions after his statement.

The person who leaked the information posted it in February to an invitation-only social media site popular with video game players.

“We continue to review a variety of factors as it relates to safeguarding classified materials,” Pentagon spokesperson Brig. Gen. Patrick Ryder in a separate press briefing.

“This includes examining and updating distribution lists, assessing how and where intelligence products are shared, and a variety of other steps.”

Teixeira will have an initial appearance at the U.S. District Court for the District of Massachusetts, Garland said.