A 21-year-old Massachusetts Air National Guard member has been arrested after allegedly posting classified information on the online social platform Discord.

Federal agents arrested Jack Douglas Teixeira, who used the alias OG on the Discord server, at his home in North Dighton, Massachusetts, on Thursday, according to CNN.

“Since late last week, the FBI has aggressively pursued investigative leads, and today’s arrest exemplifies our continued commitment to identifying, pursuing, and holding accountable those who betray our country’s trust and put our national security at risk,” an FBI spokesperson said, per CNN.

“The FBI is continuing to conduct authorized law enforcement activity at the residence,” the spokesperson added. 

Air Force spokesperson Ann Stefanek said Teixeira was a cyber transport systems journeyman at the Otis Air National Guard Base in Cape Cod. He entered the Air National Guard in 2019, BuzzFeed News reported.

Teixeira is accused of leaking classified U.S. documents exposing government secrets, such as the surveillance of its allies. He started sharing the information with an invitation-only group on Discord in late 2022, saying that he had government information that was being withheld from civilians. 

The man known as OG began posting cryptic messages about classified intelligence documents he claimed to have accessed through his job on a military base, according to a report from The Washington Post. 

The leaker first began transcribing secret documents by hand, but when that became too cumbersome, he started posting photos of the documents. He uploaded them to the private Discord server — which he named “Thug Shaker Central” — that he created for his friends in 2020. 

The documents went largely ignored by most of the small group on the private Discord server until one of the members decided to post some of the information to another Discord server in late February 2023. 

From there, another user posted some of the images onto a third Discord server focused on players of a popular video game. After that, the leaked documents began gaining traction across the internet, appearing on various websites, and eventually showing up in the Russian news media on April 5. 

The leaked documents have alienated some of America’s allies, making for an uncomfortable situation for U.S. foreign policy makers, according to The Washington Post. 

The Discord leaks show summaries of high-level conversations between world leaders and information surrounding advanced satellite technology that the U.S. allegedly uses to spy.

Some documents also included assessments of the war in Ukraine and the challenges both countries face as war efforts have stalled, CNN reported.

Other leaked documents revealed a wide range of assessments of situations in the Middle East, China, North Korea, South America, Africa, and the mercenary Wagner Group, according to ABC News Australia. 

Information was also leaked that analyzed possible scenarios if Russian President Vladimir Putin or Ukrainian President Volodymyr Zelenskyy were to die, per the Australian Broadcasting Corporation. 

“An interagency effort has been stood up, focused on assessing the impact these photographed documents could have on U.S. national security and on our Allies and partners,” Pentagon Deputy Press Secretary Sabrina Singh said in a statement, according to The Washington Post.

President Joe Biden was regularly briefed on the investigation as U.S. officials engaged with allies perturbed by the leaked information. 

“I’m not concerned about the leak. I’m concerned that it happened, but there’s nothing contemporaneous that I’m aware of that is of any consequence,” Biden said, per CNN. 

Following the leak, the Pentagon has taken measures to further restrict who may receive highly classified information, according to Defense Secretary Lloyd Austin. 

“As Secretary of Defense, I will also not hesitate to take any additional measures necessary to safeguard our nation’s secrets,” he said in a statement released by the department.

“Accordingly, I am directing the Under-Secretary of Defense for Intelligence and Security to conduct a review of our intelligence access, accountability and control procedures within the Department to inform our efforts to prevent this kind of incident from happening again,” Austin continued. 

Pentagon spokesman Brig. Gen. Patrick Ryder backed up this statement at a press briefing on Thursday, stating the Pentagon continues “to review a variety of factors as it relates to safeguarding classified materials. This includes examining and updating distribution lists, assessing how and where intelligence products are shared, and a variety of other steps.” 

“This was a major security breach that cannot be allowed to happen again,” said Senate Armed Services Committee Chairman Jack Reed (D-RI) in a statement, according to Politico. “Leaking this trove of classified information endangered our military and intelligence professionals and undermined the security of our allies and partners.” 

Teixeira appeared in a federal courtroom in Boston on Friday for an arraignment. He has been charged with the unauthorized retention and transmission of national defense information and the willful retention of classified documents, Fox News reported.

Teixeira did not enter a plea at the arraignment and is being held without bail.