Ukraine Leaks: Air National Guardsman Arrested as F.B.I. Searches His Home (Published 2023) (2024)

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An arrest has been made in the inquiry into the leaked documents. Here’s what we know.

Airman Teixeira oversaw an online Discord group named Thug Shaker Central, where about 20 to 30 people, mostly young men and teenagers, came together over a shared love of guns, racist online memes and video games.

On Thursday afternoon, around a half-dozen rifle-carrying F.B.I. agents pushed onto the property of a residence in North Dighton. Attorney General Merrick Garland said Thursday that the agency had made an arrest; the bureau said it was continuing to conduct “authorized law enforcement activity” at the residence. Mr. Garland said Airman Teixeira was accused of illegally sharing classified defense information.

Starting months ago, the authorities say, one of the users of the online group uploaded hundreds of pages of intelligence briefings into the small chat group, lecturing its members, who had bonded during the isolation of the pandemic, on the importance of staying abreast of world events.

The New York Times spoke with four members of the Thug Shaker Central chat group, where Airman Teixeira served as group administrator. While the gaming friends would not identify the group’s leader by name, a trail of digital evidence compiled by The Times led to Airman Teixeira.

Here’s what else to know:

• The Times has been able to link Airman Teixeira to other members of the Thug Shaker Central group through his online gaming profile and other records. Details of the interior of Airman Teixeira’s childhood home — posted on social media in family photographs — also match details on the margins of some of the photographs of the leaked secret documents.

• Members of Thug Shaker Central who spoke to The Times said that the documents they discussed online were meant to be purely informative and started to get wider attention only after one of the teenage members took a few dozen of them and posted them to a public online forum. The person who leaked, they said, was no whistle-blower, and the secret documents were never meant to leave their small corner of the internet.

• The leaked documents reveal sensitive material — maps of Ukrainian air defenses and a review of South Korea’s position on delivering ammunition to Ukraine — but it is the immediate relevance of the intelligence that most worries White House and Pentagon officials: Some of the documents appeared to be barely 40 days old.

What is Discord, the app where the leaked documents were found?

It uses servers — essentially, chat rooms — designed for specific groups or interests. Some have millions of members, while others are private, smaller communities.

Leaked Pentagon documents were said to have been circulating on the platform as early as March before appearing on other sites. The leaks are the latest episode in recent years in which Discord has played a key role, and enforcing its own content moderation policies has been a tricky issue.

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Jack Teixeira followed his family into the military.

Offline, Mr. Teixeira, a 21-year-old from North Dighton, Mass., followed several other relatives into the military after graduating from high school. He even missed his graduation ceremony because of basic training obligations at Lackland Air Force Base in Texas, according to posts on social media.

He finished his technical training the following year and officially entered active duty with the Massachusetts Air National Guard’s 102nd Intelligence Wing in October 2021, according to military service records. He achieved the rank of Airman First Class and was decorated with an Air Force Achievement Medal, which is awarded to junior airmen for notable achievements.

Airman Teixeira’s stepfather, Master Sgt. Thomas P. Dufault, retired from the same wing in 2019 after 34 years of service, according to a military news release.

His parents split up when he was young, and he appeared to be close to his sister, who would post baby pictures of Mr. Teixeira on social media when she wished him a happy birthday each December. He rooted for the N.B.A.’s Boston Celtics, enjoyed riding all-terrain vehicles and loved his family’s two dogs.

His friends in the online group, a Discord channel named Thug Shaker Central, said in interviews that it was a place that brought together lonely people during the pandemic. Sometimes, when they played war-themed video games, Airman Teixeira wanted to teach his friends about actual war, they said.

The F.B.I. converged on a quiet street in Massachusetts before the arrest.

He said he watched Airman Teixeira, wearing red shorts and an olive green T-shirt, walk out of his mother’s home before being detained and then questioned. When reporters from The New York Times told Paul that Airman Teixeira was accused of leaking hundreds of pages of classified U.S. documents, his face contorted as he stared off in the distance.

Paul said the authorities contacted him a few years ago, when Airman Teixeira was being vetted for his security clearance after he joined the Massachusetts Air National Guard.

“I told them I didn’t know him,” he said.

In a matter of hours, Maple Street — lined with trees and normally quiet — had become the nexus of a federal investigation into an intelligence breach that has compromised relations with American allies and revealed weaknesses in the Ukrainian military.

Multiple sport-utility vehicles and an armored vehicle descended on the home, and agents wearing helmets and flak jackets and carrying military-style assault rifles entered the property on foot. Overhead, a twin-engine surveillance plane circled.

Groups of agents entered the property on foot, apparently clearing the area before the rest of the convoy entered. After the arrest, police checkpoints at both ends of Maple Street held a crowd of residents and reporters at bay. At the mouth of the driveway, F.B.I. agents milled about as others at the house questioned Airman Teixeira.

“Right here, in my own backyard, I had no idea,” Paul said.

His initial, mistaken thought was that perhaps the florist shop owned by Airman Teixeira’s family was being raided for growing cannabis, he said.

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What is the intelligence mission of the Massachusetts Air National Guard?

The job mandates that applicants complete what the military calls a single-scope background investigation, which is required before being granted a top-secret security clearance.

It is not clear what security clearances Mr. Teixeira might have had, or how he might have gotten access to the materials that were posted online. Those questions are sure to be at the heart of the continuing investigation and any political fallout from the security breach.

When a reporter for The New York Times called the executive offices of the wing, a person identifying himself as Colonel Gordon twice directed any questions to the Department of Justice or the Federal Bureau of Investigation.

Located near the base of Cape Cod in the town of Bourne, a few miles beyond the twin bridges that link the peninsula to the southeastern Massachusetts coast, the base sprawls over thousands of inland acres, surrounded by swaths of dense pine forest. A reporter who drove onto the base late Thursday was stopped at a guard booth and asked to leave the property. A guard referred questions to the Justice Department.

The surrounding area, known as the Upper Cape, is generally viewed as more down-to-earth than the better-known, more upscale resort towns found further to the east. Residents said the number of jobs and employees on the base have declined with the years; several said they had been surprised to learn that someone working there might have been responsible in some way for the leak.

The site has been most often in the news in recent years for providing temporary housing for groups of people in urgent need of shelter. Evacuees displaced from New Orleans by Hurricane Katrina found shelter there in 2005, while last year, a group of migrants flown to Martha’s Vineyard by Florida Gov. Ron DeSantis were later moved to housing on the Bourne base.

On its official website, the wing lists its mission as providing “worldwide precision intelligence and command and control along with trained and experienced airmen for expeditionary combat support and homeland security.”

The wing commander’s biography says he is responsible for 1,260 military and civilian personnel, and their duties include responding to domestic emergencies in Massachusetts while training for wartime missions.

Those missions are given as “intelligence, surveillance and reconnaissance operations, cryptologic intelligence, cyberengineering and installation support, medical and expeditionary combat support.”

A unit at the Otis base also processes intelligence from U-2 spy planes, RQ-4 Global Hawk and MQ-9 Reaper drones and provides support to the National Geospatial-Intelligence Agency. That unit, the 102nd Intelligence, Surveillance and Reconnaissance Group, is a subordinate unit of the 102nd Intelligence Wing.

The 102nd Intelligence Wing publicly lists several job openings for airmen in signals, cryptologic and geospatial intelligence.

The state of Massachusetts has a long history with the National Guard, which was founded there on Dec. 13, 1636, according to an official website which notes that the first Guard aviation unit in Massachusetts was authorized in 1921.

Since the attacks on Sept. 11, 2001, airmen of the Massachusetts Air National Guard have flown air patrols over the East Coast. They have long supported combat operations overseas as well.

The Massachusetts Air National Guard website says that members can choose among 200 different career fields and will “learn leadership skills that today’s employers value.”

“No matter what you’re interested in,” the website says, “there’s a good chance you’ll find it here.”

The Pentagon provided little information about how Mr. Teixeira might have gotten access to the material or what security reviews might be underway.

In a statement emailed to reporters in the hours after his arrest, Defense Secretary Lloyd J. Austin III pledged his support to the Justice Department’s investigation and said that he would “continue to review the national security implications” of the unauthorized disclosure of classified material.

Mr. Austin said he would “not hesitate to take any additional measures necessary to safeguard our nation’s secrets,” and that he had directed a review of intelligence access, accountability and control procedures to inform the Pentagon’s efforts to “prevent this kind of incident from happening again.”

Anushka Patil contributed reporting.

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“The F.B.I. is continuing to conduct authorized law enforcement activity at the residence,” she said. “Since late last week the F.B.I. 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.”

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A trail of digital evidence led to a 21-year-old Air National Guardsman.

The granite countertop bearing a distinctive pattern and white floor tiles are visible in the margins of some of the leaked intelligence briefings. The same interior décor is visible in photographs of the family home posted online by one of Airman Teixeira’s immediate relatives.

Mr. Teixeira was arrested by the F.B.I. in North Dighton, Mass., on Thursday afternoon. A member of the gaming chatroom where the documents were leaked said to The Times that they thought he would have fled the U.S. by now.

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There is one key difference: Winner shared the information with the media — as opposed to the Ukraine leak, which was initially confined to a small online chat group.

Biden says the leak did not compromise intelligence ‘of great consequence.’

Asked for an update on the investigation, Mr. Biden said, “I’m concerned that it happened but there is nothing contemporaneous that I’m aware of that is of great consequence.”

The remarks were Mr. Biden’s first about the leaks since he arrived in Ireland on a three-day trip that is part personal journey and part diplomacy. The president has attempted to keep attention focused on his visit, and had previously ignored several questions from reporters about the investigation into the leaks.

Mr. Biden later spoke to Ireland’s Parliament, using the speech to continue his efforts to shore up the global alliance on behalf of Ukraine, highlighting Ireland’s humanitarian assistance and its acceptance of some 80,000 refugees who have fled Ukraine.

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Leaked documents revealed secret U.S. intelligence. What did they say?

They also revealed previously unknown information about American intelligence gathering and the actions of other countries. Here are some of the key insights found in the documents as reported by The New York Times:

• U.S. warnings that China was considering giving Russia military aid appeared to be based at least partially on intercepted communications in mid-February indicating that the Russian Foreign Intelligence Service had reported the approval of such aid by China’s top military body.

• An incident in which a Russian fighter jet fired a missile at a manned British surveillance aircraft flying over the Black Sea in September was far more serious than originally portrayed, a miscommunication that could have amounted to an act of war.

• Almost 100 special forces from five Western nations were in Ukraine in February, the first time a firm number had been made public.

• The United States could try to press Israel to provide lethal aid to Ukraine, which would be in contravention of current Israel policy to offer humanitarian assistance.

• Russia promised troops bonus pay for damaging or destroying NATO tanks.

• The United States most likely spied on South Korea, a key Asian ally, drawing denouncements in Seoul.

• The Ukrainian Army was close to losing the battle for Bakhmut, a key battleground, in February before generals deployed elite units from the military intelligence agency to push back the Russians.

• Wagner, a Russian mercenary group, has influence not just in Ukraine but all over the world, working to thwart American interests in Africa and is exploring branching out to Haiti.

• Iran and Nicaragua held discussions in February about bolstering their military cooperation as a way of countering American influence in Latin America.

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Once shocking, U.S. spying on its allies now draws a global shrug.

That was a decade ago, after an enormous leak of classified documents detailing American surveillance programs by the former National Security Agency contractor Edward Snowden, who provided them to journalists in what he called a public service to expose government overreach.

The latest leak of classified documents that appeared online this year, the motive behind which remains unknown, has again illustrated the broad reach of U.S. spy agencies, including into the capitals of friendly countries such as Egypt, South Korea, Ukraine and the United Arab Emirates.

Though the documents mainly focus on the war in Ukraine, they include C.I.A. intelligence briefs describing conversations and plans at senior levels of government in those countries, in several cases attributed to “signals intelligence,” or electronic eavesdropping. They have served to remind the world of America’s talent for spying — and the diplomatic blowups and reputational damage stemming from the leaks.

The United States’ adversaries have sought to exploit the awkward moment. It was only months ago that U.S. officials were condemning Beijing for its prying eyes, in the form of spy balloons drifting over multiple continents. On Wednesday, China’s foreign ministry spokesman turned the tables, insisting that the United States owed the international community an explanation for its “indiscriminate secret theft, surveillance and eavesdropping on countries in the world, including its allies.”

Unlike in 2013, however, U.S. allies appear to be mostly shrugging off the latest examples of apparent spying.

The governments of Egypt, Israel, South Korea, and the United Arab Emirates called leaked reports about their deliberations false or fabricated but said little or nothing about the surveillance itself. (U.S. officials have not disputed the overall authenticity of the documents, though they have warned without offering specifics that some of the contents may have been altered since appearing online.)

The subdued response may be the product of a jaded view about the long reach of U.S. spy agencies. The end of the Cold War may have brought a golden era of espionage to a close, but the documents that Mr. Snowden leaked in 2013 revealed that a new age of spying had begun after September 2001. It became clear that the United States, driven by fears of foreign terrorism and empowered by technological advances, had created a sophisticated network of global surveillance that was scooping up vast amounts of data from millions of emails and phone calls around the world.

It was shocking to many at the time. Less so today.

“I would expect the reaction to this latest leak to be far more muted than the reaction to the Snowden disclosures,” said Charles Kupchan, who became the White House National Security Council’s senior director for Europe less than a year after those leaks.

“Snowden let the cat out of the bag” by revealing the full extent of American surveillance worldwide, Mr. Kupchan said. “To some extent, the fact that the U.S. is spying on allies is old news,” he added.

That may be a relief for President Biden. President Barack Obama, under whom Mr. Kupchan served, found himself working the phones to clean up damage from the revelations of surveillance of allies.

Perhaps most explosive was the follow-up revelation by WikiLeaks, two years after Mr. Snowden’s leaks, that the N.S.A. had directly targeted Chancellor Angela Merkel’s phone, which led her to tell Mr. Obama, as she later recounted, that “spying on friends is not acceptable.” Political rivals criticized Ms. Merkel for allowing the United States to trample on Germany’s sovereignty, and German public opinion toward the country soured.

Mr. Obama acknowledged the damage during a meeting in February 2015 with the German leader, telling reporters as they sat together in the Oval Office that there was “no doubt that the Snowden revelations damaged impressions of Germans with respect to the U.S. government and our intelligence cooperation.”

Brazilian politics was similarly inflamed when the Snowden documents revealed that the N.S.A. had been monitoring the emails and phone calls of President Dilma Rousseff. A personal appeal from Mr. Obama in a 20-minute phone call was not enough to prevent a furious Ms. Rousseff from canceling a state visit to Washington planned for the next month. Soon after, she castigated the United States in remarks at the United Nations for “an affront to the principles that should otherwise govern relations among countries, especially among friendly nations.”

Mr. Obama appealed to France, first after a 2013 revelation that the N.S.A. had surveilled its citizens and business and political leaders, and again after the disclosure that Washington had spied on not one but three recent French presidents. Mr. Obama phoned President François Hollande toassure him that the practice had ended.

Polling by the Pew Research Center later found that those disclosures had harmed the United States’ public image, but not gravely. A Pew survey of 44 countries found widespread opposition to U.S. covert surveillance, with more than 73 percent of respondents saying they opposed spying on their leaders. The survey also showed Mr. Obama’s approval ratings had plunged in Germany and Brazil. But global opinion about the United States remained positive overall.

It is too early to say how public opinion might be affected by the classified documents that were recently discovered online, but there are few indications of a major backlash. Benjamin Rhodes, a former deputy national security adviser in the Obama administration, said he expected little outcry.

One key reason, he said, was that the documents leaked by Mr. Snowden revealed not only spying on world leaders but also mass surveillance of populations, angering people who felt that their everyday privacy might have been violated.

“That created more of a political problem for the leaders,” Mr. Rhodes said. “There was some performative outrage, in part because it was about the emails of” their people.

There had also been “a normalization of these leaks,” he said, citing not only the N.S.A. files Mr. Snowden released but also a huge trove of State Department diplomatic cables given to WikiLeaks by Chelsea Manning, the former Army intelligence analyst.

“By this point, I just can’t imagine that anybody could credibly be shocked to learn that the U.S. is interested in decision-making in these countries,” Mr. Rhodes said.

Some purported examples of that decision-making include Egypt’s plans to secretly supply Russia with munitions to use in Ukraine, a deepening of ties between the Emirati and Russian intelligence services, deliberations about war strategy in Ukraine, and support for antigovernment protests from officials in Mossad, Israel’s spy agency. (The Washington Post reported on the intelligence about Egypt, and The Associated Press reported on the United Arab Emirates based on documents they exclusively obtained. Both governments have denied the allegations.)

So far, the only evident political fallout from the latest leaks has occurred in South Korea, where one classified U.S. document described a debate among senior national security officials about whether to send artillery shells abroad that might wind up in Ukraine, potentially angering Russia. Opposition leaders in South Korea have denounced the United States for breaching trust with an ally and “violating the sovereignty” of the country.

But that might be mostly a matter of domestic political grandstanding, said Andrew Yeo, a senior fellow at the Brookings Institution’s Center for East Asia Policy Studies, as South Korea’s opposition Democratic Party works to undermine the government of President Yoon Suk Yeol.

Mr. Yoon, keen on a close alliance with the United States, has little interest in a diplomatic row with Mr. Biden. And South Koreans may be tolerant of the eavesdropping given their highly favorable attitudes toward the United States, in part because they see Washington as an important guardian against China’s growing power.

“I don’t think it’s anywhere near the sort of reaction that we got” a decade ago, Mr. Yeo said. “I don’t think it’s going to damage the alliance in the long term.”

He added, “It’s more of an embarrassment that the U.S. is still having to spy on its friends.”

The latest leaked documents differ from past intelligence breaches.

Some of the most sensitive material — maps of Ukrainian air defenses and a deep dive into South Korea’s secret plans to deliver 330,000 rounds of much-needed ammunition in time for Ukraine’s spring counteroffensive — is revealed in documents that appear to be barely 40 days old.

It is the freshness of the “secret” and “top secret” documents, and the hints they hold for operations to come, that make these disclosures particularly damaging, administration officials say. On Sunday, Sabrina Singh, a Pentagon spokeswoman, said U.S. officials had notified congressional committees of the leak and referred the matter to the Justice Department, which had opened an investigation.

The 100-plus pages of slides and briefing documents leave no doubt about how deeply enmeshed the United States is in the day-to-day conduct of the war, providing the precise intelligence and logistics that help explain Ukraine’s success thus far.

They also reinforce how deeply American spy agencies have penetrated nearly every aspect of the Russian intelligence apparatus and military command structure.

The United States is providing detailed targeting data. It is coordinating the long, complex logistical train that delivers weapons to the Ukrainians. And as a Feb. 22 document makes clear, American officials are planning ahead for a year in which the battle for the Donbas is “likely heading toward a stalemate” that will frustrate Vladimir V. Putin’s goal of capturing the region — and Ukraine’s goal of expelling the invaders.

One senior Western intelligence official summed up the disclosures as “a nightmare.”

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F.B.I. Arrests National Guardsman in Leak of Classified Documents

Airman First Class Jack Douglas Teixeira was taken into custody to face charges of leaking classified documents after federal authorities said he had posted batches of sensitive intelligence to an online gaming chat group, called Thug Shaker Central.

As reporters from The New York Times gathered near the house on Thursday afternoon, about a half-dozen F.B.I. agents pushed into the home of Airman Teixeira’s mother in North Dighton, with a twin-engine government surveillance plane keeping watch overhead.

Some of the agents arrived heavily armed. Law enforcement officials learned before the search that Airman Teixeira was in possession of multiple weapons, according to a person familiar with the investigation, and theF.B.I. found guns at the house.

Not long after, cameras caught a handcuffed Airman Teixeira, wearing red shorts and boots, being led away from the home by two heavily armed men.

In Washington, Attorney General Merrick B. Garland, in a brief statement, announced the arrest and said Airman Teixeira would be arraigned at the Federal District Court in Massachusetts. Mr. Garland said he was arrested in connection with the “unauthorized removal, retention and transmission of classified national defense information,” a reference to the Espionage Act, which is used to prosecute the mishandling and theft of sensitive intelligence.

The arrest raised questions about why such a junior enlisted airman had access to such an array of potentially damaging secrets, why adequate safeguards had not been put in place after earlier leaks and why a young man would risk his freedom to share intelligence about the war in Ukraine with a group of friends he knew from a video game social media site.

A motive in the case for now remains elusive. But, according to people who knew him online, Airman Teixeira was no whistle-blower. Unlike previous huge leaks of information, from the Pentagon Papers to WikiLeaks to Edward Snowden’s disclosures, outrage about wrongdoing or government policies does not appear to have been a factor.

Indeed, the disclosures were potentially damaging to all parties in the Ukraine war as well as future intelligence collection. While some officials, including President Biden, have downplayed the damage from the leak, it will take months to learn whether U.S. intelligence loses access to important methods of collection because of the disclosures.

The F.B.I. had been zeroing in on Airman Teixeira for several days, tracking its own investigative clues as well as some of the same information that The Times and The Washington Post had developed about the Discord group where he had shared the documents, officials said.

Still, as reporters uncovered more information, law enforcement officials had to speed up their investigation.

While federal investigators believed that Airman Teixeira could pose a danger to agents conducting the search, his online friends knew him as a sometimes hectoring leader of their small community.

Several months ago, a user of Thug Shaker Central known as O.G. began uploading hundreds of pages of intelligence briefings into the small chat group. The group also discussed guns and military equipment, as well as the original subject of their group, video games.

While the members of the chat group would not identify the group’s leader by name, a trail of digital evidence compiled by The Times led to Airman Teixeira. American officials have confirmed that they believe he uploaded the information taken improperly from U.S. military computers.

As he posted the material, O.G. lectured the group’s members, who had bonded during the isolation of the pandemic, on the importance of staying abreast of world events.

Airman Teixeira was trained as a cyber transport systems specialist, a job that could entail a variety of duties, such as keeping his unit’s communication networks running. He was assigned to the 102nd Intelligence Wing at Otis Air National Guard Base, part of Joint Base Cape Cod, according to an Air Force spokeswoman. The 102nd Intelligence Wing’s official Facebook page congratulated Airman Teixeira and colleagues on their promotion to airmen first class in July.

Officials would not answer questions about what in Airman Teixeira’s duties would necessitate his havingaccess to daily slides about the Ukraine war, much less the daily deluge of intelligence reports from the C.I.A., the National Security Agency and the Office of the Director of National Intelligence. There are units at the base that process intelligence collected from drones and U-2 spy planes, though it is doubtful that work alone would require the sort of access to the broad array of classified information that has been leaked on the Discord server.

But he could also have gained access to the documents in other ways. U.S. government officials with security clearance often receive such documents through daily emails on a classified computer network, one official told The Times, and those emails might then be automatically forwarded to other people.

Airman Teixeira’s mother, Dawn, speaking outside her home in North Dighton on Thursday, confirmed that her son was a member of the Air National Guard and said he had recently been working overnight shifts at a base on Cape Cod. In the past few days, he had changed his phone number, she said.

Later, someone who appeared to be Airman Teixeira drove onto the property in a red pickup truck.

When Times reporters approached the house again, the truck was parked in the driveway. Airman Teixeira’s mother and his stepfather were standing in the driveway.

When asked if Airman Teixeira was there and willing to speak, his stepfather, Thomas P. Dufault, said: “He needs to get an attorney if things are flowing the way they are going right now. The feds will be around soon, I’m sure.”

Within a few hours, the prediction of Mr. Dufault, a retired Air Force master sergeant, proved correct as F.B.I. and other government personnel drove onto the property.

A neighbor, Paul Desousa, looked on as the F.B.I. agents yelled Airman Teixeira’s name. The neighbor said the young man then walked out of the house.

Mr. Desousa did not know Airman Teixeira, but said he had frequently heard him fire weapons in the woods behind his house.

After Airman Teixeira was led away, the search of the property continued. And as the sun began to set, a food delivery truck arrived for the F.B.I. agents scouring Airman Teixeira’s family home, a sign that the search was likely to continue for several hours.

Members of Thug Shaker Central who spoke to The Times said that the documents they discussed online were meant to be purely informative. While many pertained to the war in Ukraine, the members said they took no side in the conflict.

The documents, they said, started to get wider attention only when one of the teenage members of the group took a few dozen of them and posted them to a public online forum. From there they were picked up by Russian-language Telegram channels and then The Times, which first reported on them.

In Washington, the crisis over the leaks began late last week, as some documents began surfacing on Telegram and Twitter.

Defense Secretary Lloyd J. Austin III was initially briefed on the leak on the morning of April 6. Pentagon officials tried to get some of the Telegram and Twitter posts showing pictures of some of the documents that initially came to light deleted, but they were unsuccessful.

The next day, last Friday, Mr. Austin began convening departmentwide meetings to address the growing disclosures. Pentagon and other U.S. officials began contacting congressional leaders and allies to alert them to the leaks, which have ignited political firestorms in some countries.

Also last Friday, the military’s Joint Staff, which had produced many of the briefing slides that were leaked, instituted procedures to limit the distribution of highly sensitive briefing documents and restrict attendance at meetings where briefing books containing paper copies of the documents were available.

On Tuesday, in his first public comments about the leaks, Mr. Austin struggled to explain why the Defense Department only learned about the leaks long after they first surfaced on Discord.

“Well, they were somewhere in the web,” Mr. Austin said of the leaked documents. “And where exactly and who had access at that point, we don’t know. We simply don’t know at this point.”

Even as Mr. Austin spoke, news outlets began writing about discoveries of more documents.

On Thursday morning, Mr. Austin called a meeting with senior staff members to discuss the crisis.

But by then the F.B.I. was already preparing the search warrant for the home in North Dighton, and investigators began assuring Pentagon officials that the leaker would soon be caught.

Reporting and research were contributed by Riley Mellen, Adam Goldman, Michael Schwirtz, Helene Cooper, Eric Schmitt, John Ismay, C.J. Chivers, Michael D. Shear, Kitty Bennett and Sheelagh McNeill.