Law enforcement officials have linked a trove of classified government documents leaked on Discord to a 21-year-old Air Force National Guard member, as reported earlier by NBC News. The suspect, Jack Teixeira, was arrested at his home in North Dighton, Massachusetts, on Thursday.

“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,” Attorney General Merrick Garland said in a statement.

The Pentagon first discovered the sensitive documents posted to Discord, Twitter, Telegram, and 4chan last week. The leaks revealed details about the Russia-Ukraine war along with information about the US’s efforts to spy on Russia and its allies. Some of these leaked documents might even trigger diplomatic issues, as one reportedly reveals that Serbia may have supplied Ukraine with lethal aid, potentially straining its relationship with Russia.

The documents were initially found with apparent alterations, like a file on one Telegram channel suggesting that Ukraine had lost more soldiers in the war with Russia than what was documented. Later investigations determined that unaltered versions had been posted earlier than previously believed and were then spread to other channels by third parties. An investigation from Bellingcat found that the documents may have been posted as far back as January.

According to a report from The Washington Post, the original leaker was known as “OG” within the private Discord server “Thug Shaker Central,” where he also served as the administrator. The suspect reportedly posted typed-up versions of the documents to the server, but he later transitioned to sharing actual photos with the group after growing frustrated by the members’ lack of interaction with them. The background of these photographs, which contained interior decorations, countertops, and flooring, helped the FBI make the connection to Teixeira, according to The New York Times.

During a press conference on Thursday, Department of Defense press secretary Patrick Ryder declined to comment on how many documents were leaked, while stating that law enforcement is still investigating. Ryder also added that Discord is cooperating with the Department of Justice’s investigation, which the company publicly announced on Wednesday. Discord didn’t immediately respond to The Verge’s request for comment.

“We have safeguards in place, we have processes, we have procedures, and will continue to do due diligence as part of this review to ensure that we’re doing everything we can to prevent potential unauthorized disclosures in the future, recognizing that again, this was a criminal, deliberate act,” Ryder said.