Pentagon leak suspect Jack Teixeira to appear in federal court Friday

Jack Teixeira, the 21-year-old Air National Guardsman accused of leaking classified intelligence documents online in recent months, will appear in a Boston federal courtroom Friday morning, sources tell Fox News. 

FBI agents arrested Teixeira at his home in North Dighton, Massachusetts, Thursday without incident. Attorney General Merrick Garland said the young man is being investigated for the "alleged unauthorized removal, retention and transmission of classified national defense information." He will make his first court appearance in the U.S. District Court for the District of Massachusetts sometime Friday between 10 a.m. and 2 p.m., according to a source with the U.S. Attorney's Office for the District of Massachusetts. 

Teixeira joined the Air National Guard in September 2019 and worked as a cybersecurity systems journeyman, a position in which he held the highest level of security clearance granted by the federal government for top secret information, according to an internal Department of Defense email reviewed by Fox News. 

His security clearance and access to classified government systems have since been revoked, according to another internal government document.

WHO IS JACK TEIXEIRA, THE AIR NATIONAL GUARDSMEN ALLEGEDLY BEHIND LEAKED CLASSIFIED DOCUMENTS?

Teixeira was most recently stationed at Otis Air National Guard Base in Cape Cod as a member of the 102nd Intelligence Wing. He was promoted to airman first class in July, according to the unit.

In a call with members of Thug Shaker Central, a panicked Teixeira seemed to know he was in trouble. One of the group members, who uses the screen name Vahki, recounted to The New York Times that Teixeira sounded as if he was in a speeding car the last time they spoke.

"Guys, it’s been good – I love you all," Teixeira said, according to Vahki. "I never wanted it to get like this. I prayed to God that this would never happen. And I prayed and prayed and prayed. Only God can decide what happens from now on."

Details of the leaked Pentagon documents were reported last week by The Washington Post, which obtained dozens of what appeared to be photographs showing classified intelligence briefings detailing Ukraine's combat abilities, information about the Ukrainian and Russian militaries, and highly sensitive analysis about U.S. allies and adversaries, including China. 

President Biden has said nothing leaked was "of great consequence," but White House national security spokesman John Kirby warned Wednesday, "We don't know what else this individual or individuals might have and might still release." 

"You've got highly sensitive classified information now in the public domain, and that's simply unacceptable and could do damage to our national security," Kirby said. 

FBI ARRESTS MASSACHUSETTS AIR NATIONAL GUARDSMAN JACK TEIXEIRA IN PROBE OF CLASSIFIED DOCUMENT LEAKS

The FBI began surveilling Teixeira in connection with the leaks before Thursday but were forced to accelerate their plans to arrest him after The New York Times identified him on Thursday morning, a source briefed on the investigation told Fox News. 

The report named Teixeira as the leader of a Discord group called "Thug Shaker Central" that consisted of roughly 20 to 30 young men. Discord is an instant messaging social media platform popular with gamers – members of Thug Shaker Central reportedly bonded during the pandemic by playing video games together, sharing memes and discussing guns.

Group members who spoke to the New York Times said Teixeria began posting classified documents in October, including detailed battle maps from the war in Ukraine labeled "TOP SECRET." Between October and March he reportedly posted about 350 documents to the group. His motivation appears to be wanting to inform and impress his online friends with inside knowledge of events happening abroad. 

The classified materials began circulating more widely after another member of the group posted several dozen documents to a public Discord chat called #War-Posting, according to the outlet. By April, classified U.S. intelligence on Ukraine was being posted on the Telegram messaging app by supporters of Russia's invasion of Ukraine. 

U.S. defense officials previously told Fox News the leak could be "bigger than Snowden" in terms of damage to intelligence and allied relationships.

PENTAGON DOCUMENT LEAK HAS IMMEDIATE IMPACT ON NATIONAL SECURITY: SUCKS UP ‘A LOT OF OXYGEN’

Pentagon press secretary Brig. Gen. Pat Ryder called the leaks "a deliberate criminal act," saying that distribution lists for classified information are being reviewed. 

"We entrust our members with a lot of responsibility at a very early age," Ryder told reporters Thursday. 

"You've received training, and you will receive an understanding of the rules and requirements that come along with those responsibilities. And you're expected to abide by those rules, regulations and responsibility. It's called military discipline. And, in certain cases, especially when it comes to sensitive information, it also is about the law."

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Fox News' Greg Norman, David Spunt, Liz Friden, Gillian Turner, Jake Gibson and Paul Best contributed to this report.