PENTAGON leak suspect Jack Teixeira was "trying to be impressive" and remained undefeated during his arrest, a body language expert has revealed.

Teixeira, a 21-year-old United States National Guardsman, was arrested at his North Dighton, Massachusetts home on April 13 for allegedly distributing secret defense and intelligence documents online.

Jack Teixeira, a 21-year-old US national guardsman was arrested in his North Dighton, Massachusetts home for allegedly leaking secret documents

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Jack Teixeira, a 21-year-old US national guardsman was arrested in his North Dighton, Massachusetts home for allegedly leaking secret documentsCredit: Reuters
Teixeira's head was 'slightly bowed' as he was led away in handcuffs by authorities on April 13

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Teixeira's head was 'slightly bowed' as he was led away in handcuffs by authorities on April 13Credit: AP

The leak was traced back to a Discord chat of video gamers titled Thug Shaker Central.

Teixeira was allegedly part of the chat group, who confirmed the docs were sent by a friend.

A judge ruled on Friday that he must remain behind bars until his trial, the Associated Press reported.

US Magistrate David Hennessy called Teixeira's alleged offense "a profound breach of the defendant’s word that he would protect information related to the security of the United States."

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Body language expert and multi-published author Greg Williams exclusively told The U.S. Sun that Teixeira was "trying to be impressive with putting secrets out and he probably did not think the whole situation through."

"Jack is 21 years old. Think about when you were 21 and the bravado that you may have had," Williams, known as The Master Negotiator, added.

Williams said Jack probably thought he would get some "fanfare" and didn't think about the repercussions.

Video of the arrest was released showing Teixeira's head "slightly bowed" while walking in handcuffs beside authorities.

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"He was slightly bowed, but still not to the point where he felt the weight of the world on him," Williams said.

"And he wasn't completely upright, which said, 'okay, you got me. What's next?'"

A day after his arrest, Teixeira was charged in a Boston court with two federal counts under the Espionage Act - unauthorized detention and transmission of national defense information and unauthorized removal of classified information and defense materials.

The documents reportedly contained information about the Ukraine war and China, among other things.

About 20 to 30 young men and boys were in the Discord chat where the docs were initially leaked.

Members of the group confirmed that the chat organizer, known to them as O.G., sent the classified information, saying that he told them they came from his job.

"He's a smart person," an unnamed member told The Washington Post.

"He knew what he was doing when he posted these documents, of course. They weren't accidental leaks of any kind."

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The group notably refused to share the leaker's identity and maintained that he was a good person who just wanted to "keep us in the loop."

Teixeira is scheduled to appear in court again on Friday afternoon.

Body language expert Greg Williams said Teixeira was full of 'bravado' before he was caught

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Body language expert Greg Williams said Teixeira was full of 'bravado' before he was caughtCredit: The US Sun
Teixeira was charged in a Boston court with two federal counts under the Espionage Act a day after his arrest

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Teixeira was charged in a Boston court with two federal counts under the Espionage Act a day after his arrestCredit: Reuters