When the newly minted member of the Massachusetts Air National Guard returned home from training, his mother took to her flower shop’s Facebook page to express pride in his accomplishments.

“Jack is on his way home today, tech school complete, ready to start his career in the Air National Guard!” said the post, dated June 3, 2021. It was accompanied by a photograph of a patriotic-themed balloon tied to a mailbox and emblazoned, “Welcome home!”

Patriotic zeal appeared common around Airman 1st Class Jack Teixeira, 21, who had followed in the footsteps of numerous family members to join the military. Teixeira, slim and boyish in photographs taken in his blue dress uniform, had been assigned to manage and troubleshoot computers and communications systems for the 102nd Intelligence Wing at Otis Air National Guard Base, according to the Air Force.

Investigators now think there’s a more troubling, reckless side to Teixeira — and the fallout is only beginning.

FBI agents clad in body armor and carrying rifles swept across the Teixeira family residence in Dighton, Mass., on Thursday, arresting Teixeira and charging him with unauthorized removal of classified national defense information, Attorney General Merrick Garland said in brief remarks at the Justice Department. Video captured by news helicopters circling over the family home showed him at one point holding his hands behind his head under the watch of law enforcement personnel, before he was led away while wearing red athletic shorts and a T-shirt.

Teixeira has been identified as the suspected leaker of hundreds of photographs of highly classified military documents that have proliferated across the internet over the past week. The leak, probably the military’s largest in at least a decade, has revealed secrets about everything from gaps in Ukrainian air defenses to the specifics of how the United States spies on its allies and partners.

Teixeira, who used online handles that include “jackthedripper” and “excalibureffect,” posted the images to Discord, a chat platform popular with gamers, people familiar with the case said. Some Discord members showed The Washington Post video of Teixeira shouting racist and antisemitic slurs before firing a rifle. Like some others interviewed for this story, they spoke on the condition of anonymity because of the sensitivity of the issue.

The arrest appeared to bring to an end a weeklong mystery that both law enforcement officials and internet sleuths had attempted to unravel. The photos of documents posted online included a trail of clues, with items in the background that included Gorilla Glue, a Boston Red Sox hat and hunting magazines.

Attempts to reach Teixeira and members of his family were unsuccessful. Senior officials with Teixeira’s unit referred questions to the Defense Department.

The crisis has blindsided the Pentagon, which did not become aware until last week that secrets had for weeks been spreading online, and forced the Biden administration to have awkward conversations with allies and partners about explosive issues. The FBI did not descend on the Teixeira home until after The Post revealed numerous details about the still-anonymous leaker on Wednesday night and after the New York Times followed up on Thursday by naming Teixeira.

Defense Secretary Lloyd Austin commended the Justice Department and FBI for their “swift action in connection with this investigation” and pledged full Defense Department support for it.

The Pentagon continues to assess the damage to national security that has occurred because of the leak, he said. Each service member, Defense Department employee, and defense contractor with classified information “has a solemn legal and moral obligation to safeguard it and to report any suspicious activity or behavior.”

While Teixeira was relatively inexperienced in the military, he had access to highly classified military intelligence through a Defense Department computer network known as the Joint Worldwide Intelligence Communications System, said a U.S. official familiar with the matter. The system would have allowed Teixeira to read and potentially print classified documents, though there are guidelines to handle those in accordance with the law.

Teixeira was mobilized for federal active duty last fall, said Nahaku McFadden, a spokesperson for the National Guard Bureau. It is not uncommon for troops in the National Guard to receive such orders to fill the need for specialized jobs, but since he was on active duty at the time of the alleged disclosures, he is subject to additional punishment under the military justice system.

One friend described Teixeira in an interview as patriotic, a devout Catholic and a libertarian with an interest in guns and doubts about America’s future. The friend said he met Teixeira before 2020 on a Discord server mainly focused on guns and libertarian politics, and bonded over their shared interest in Glock handguns and Catholicism.

Later, the friend joined a new Discord server that Teixeira started called Thug Shaker Central, which became home to a group of about two dozen people, including many teenagers. Teixeira was a “pretty normal guy” outside the server, said the friend, who eventually met Teixeira in person. He had a “slight temper” and was “more of a mentor than a leader.”

The friend recalled that Teixeira started sharing classified documents on the Discord server around February 2022, at the beginning of the war in Ukraine, which he saw as a “depressing” battle between “two countries that should have more in common than keeping them apart.” Sharing the classified documents was meant “to educate people who he thought were his friends and could be trusted” free from the propaganda swirling outside, the friend said. The men and boys on the server agreed never to share the documents outside the server, since they might harm U.S. interests.

“I was of the opinion that some of these kids were prone to run their mouths because they spent too much time online, but I was ignored,” said the friend, who added that he tried to stay out of such discussions. “It was pretty obnoxious to see kids who grew up in the suburbs argue about a conflict an ocean away.”

Around half of the server’s members were “kids in their basements” playing video games, while the other half were gun enthusiasts, the friend said. Recent claims by others who were on the server that some of its members were Russian and Ukrainian were “pure fabrication,” the friend said. One member pretending to be a Russian naval officer actually lived in Kentucky, he said, and was kicked out.

“It was only supposed to be keeping kids informed about real-world issues,” the friend said.

Another member of the server eventually shared the documents on another server, leading to their spread across the internet.

Teixeira didn’t seek to undermine national security but hoped to teach the mostly younger members on his server “a better view of the issue the only way he knew how,” the friend said.

“He loved America but simply didn’t feel confident in its future,” the friend said. “At the end of the day he would side with this country over any other.”

Other members of Teixeira’s server have showed The Post video of Teixeira shouting racist and antisemitic slurs before firing a rifle and said he referenced government raids at Ruby Ridge in Idaho and in Waco, Texas — events with deep resonance among right-wing, anti-government extremists. The name of the Discord server itself derives from a meme taken from a gay porn video often used for its shock value and laughs, the members said.

Regarding the racist and antisemitic jokes reportedly shared on the server, the friend said it was hard to assess Teixeira’s true feelings given “how many layers of irony that server was in.” Dark jokes got more laughs, he said. But Teixeira was a “pretty basic-brand Catholic who was into guns,” the friend said.

“He’s a good person that trusted the wrong people, in my opinion,” the friend said. He said Teixeira would remain his friend and that he hoped to reschedule a hiking trip they had planned together.

For the Teixeira family, the alleged spilling of military secrets appears at odds with decades of military service.

The airman’s stepfather, Thomas Dufault, retired after a 34-year military career as a master sergeant from the same unit, the 102nd Intelligence Wing, in a 2019 ceremony at Joint Base Cape Cod, according to public records and photos posted online by the Defense Department.

Teixeira’s mother, Dawn Dufault, for years worked for nonprofit organizations supporting veterans, including the Massachusetts Military Heroes Fund and Home for Our Troops, and briefly for the Massachusetts Department of Veterans Services, according to her LinkedIn profile and public records. Since 2017, she has focused on her flower business.

Neither Dufault responded to requests for comment.

Teixeira was taken into custody at a single-family home owned by his mother on a tree-lined street in a rural neighborhood. Dighton, home to about 8,000 people, is in the southeastern corner of Massachusetts, and about 50 miles west of the military base where Teixeira worked on the southern end of Cape Cod.

A profile for Teixeira on Steam, another online site popular with gamers, includes a profile image of a man holding a rifle that crops out the head. Teixeira used the handle “TheExcaliburEffect” on the site, and featured a famous but unattributed quote:

“Beware the quiet man. For while others speak, he watched. And while others act, he plans. And when they finally rest . . . he strikes.”

The Washington Post’s Dalton Bennett, Cate Brown, Alice Crites, Chris Dehghanpoor, Shane Harris, Drew Harwell, Samuel Oakford and Jon Swaine contributed to this report.

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