Jack Teixeira, the Massachusetts Air National Guardsman suspected of leaking classified Pentagon intelligence on the war in Ukraine, may have posted sensitive information online months earlier than previously known and to a much wider chat group, according to the New York Times.

Teixeira, 21, was arrested on April 13 following an FBI investigation into the "alleged unauthorized removal, retention and transmission of classified national defense information." A cybersecurity journeyman for the Air National Guard, Teixeira held the highest level of security clearance granted by the federal government for top secret information. He is accused of posting secret intelligence on the Russian war effort to a private chat group on Discord, a social media messaging platform that is popular with gamers. The New York Times reported that the group, Thug Shaker Central, had about 50 members.

However, another Discord user told the paper about a larger, previously undisclosed, chat group with about 600 members where Teixeira allegedly posted additional classified information. 

"The newly discovered information posted on the larger chat group included details about Russian and Ukrainian casualties, activities of Moscow’s spy agencies and updates on aid being provided to Ukraine. The user claimed to be posting information from the National Security Agency, the Central Intelligence Agency and other intelligence agencies," the Times reported.

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Jack Teixeira image over Pentagon

This photo illustration created on April 13, 2023, shows a reflection of the suspect, national guardsman Jack Teixeira, among an image of the Pentagon.  (STEFANI REYNOLDS/AFP via Getty Images)

This second chat group was publicly listed on a YouTube channel and easily accessed in seconds by New York Times reporters. The posts to this group were linked to Teixeira through a "chain of digital evidence" including a username previously connected to Teixeira; statements that the poster worked for a U.S. Air Force Intelligence unit; details in videos and photos that matched images posted by family members inside the Teixeira home in North Dighton, Mass., and other details.

A public defender representing Teixeira and officials from the FBI and Justice Department declined the New York Times' requests for comment.

The first leak came within 48 hours of Russia's invasion of Ukraine in February 2022. "Saw a pentagon report saying that ⅓rd of the force is being used to invade," the user wrote, according to the report. 

"I have a little more than open source info. Perks of being in a USAF intel unit," he wrote back to members of the group who questioned his intelligence. 

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Leaked documents suspect Jack Teixeira appears in court in Boston in court sketch

Massachusetts Air National Guardsman Jack Teixeira, seated second from right, appears in U.S. District Court, in Boston, Wednesday, April 19, 2023. Teixeira, charged with leaking highly classified military documents, made a brief court appearance Wednesday. A hearing to determine whether he should remain jailed while awaiting trial has been delayed to give the defense more time to prepare. (AP Photo/Margaret Small)

Other posts reportedly displayed knowledge of troop movements before they happened. A March 27, 2022, post shared classified information about the Russian pullback from Kyiv two days before it happened. 

"Some ‘big’ news," the user wrote. "There may be a planned withdrawal of the troops west of Kiev, as in all of them."

He said this information was "found on an NSA site." 

The New York Times found posts updating the chat group on casualty numbers, Ukraine's targeting priorities and "the activities of Russian intelligence agencies." 

In one message, the user reportedly bragged, "The job I have lets me get privilege's above most intel guys." In another, Teixeira allegedly offered to share classified information privately with members of the group living outside the United States. "DM me and I can tell you what I have," he wrote, according to the New York Times.

The leaker also claimed to have access to intelligence from U.S. allies, including the Government Communications Headquarters, the British agency for intelligence, security and cyber affairs. "I usually work with GCHQ people when I’m looking at foreign countries," he wrote in September 2022. 

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Department of Defense

The Pentagon, seen from Air Force One, March 2, 2022. (AP Photo/Patrick Semansky, File)

Posts sharing classified information continued in the larger chatroom until last month. 

"I was very happy and willing and enthusiastic to have covered this event for the past year and share with all of you something that not many people get to see," the leaker wrote on March 19. "I’ve decided to stop with the updates."

Teixeira has been charged with unauthorized retention and transmission of classified national defense information. He could also face charges under the Uniform Code of Military Justice as a result of being on active duty at the time of the alleged leaks.

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A federal judge on Wednesday delayed Teixeira's detention hearing at the request of the defense, postponing it for about two weeks. 

Fox News' Michael Lee, Timothy H.J. Nerozzi and Tamara Gitt contributed to this report.