Federal prosecutors are pleading with a judge to keep behind bars the Massachusetts Air National Guardsman suspected of leaking highly classified military records, claiming he could still have access to sensitive national defense information.

Justice Department attorneys claimed in court documents filed late on Wednesday that releasing 21-year-old Jack Teixeira from custody while he awaits trial would pose a serious risk to US national security.

Investigators are still trying to figure out if Teixeira stored any hard or digital copies of sensitive documents, including ones that are yet to be made public, the papers said.

"There simply is no condition or combination of conditions that can ensure the Defendant will not further disclose additional information still in his knowledge or possession," prosecutors said. "The damage the Defendant has already caused to the U.S. national security is immense. The damage the Defendant is still capable of causing is extraordinary."

From career to court

21-year-old Airman 1st Class Jack Teixeira was arrested on April 13 at his house in Dighton, Massachusetts by heavily armed FBI agents.

Teixeira, a member of the Massachusetts Air National Guard for over four years, was apparently assigned to manage and repair computers and communications systems for the 102nd Intelligence Wing at Otis Air Base and came from a military background.

Teixeira has been in jail since his arrest on charges stemming from the highest-profile intelligence leak in years. A detention hearing is scheduled for Thursday in a federal court.

According to reports, a Pentagon official justified the Department of Defense's severe intelligence breach by saying, "We entrust our members with a lot of responsibility at a very early age."

Teixeira's counsel has stated they would ask the judge to release him so that he may go home with his father, according to the prosecution's filing. Teixeira's legal representatives were yet to submit any court documents requesting his release as of late Wednesday.

Read more: New batch of leaked documents: Ukraine, China, Middle East info reveal

The defendant has been accused of improper possession and dissemination of sensitive national security information under the Espionage Act. He has not yet filed a plea, and following the hearing last week, his counsel declined to talk to the media.

If convicted, it is believed that the airman will face up to 25 years in prison.

Some of the most sensitive leaked details are purportedly related to Ukraine's military capabilities and shortcomings, as well as information about US allies, including the Israeli occupation, South Korea, and Turkey.

Read more: Mossad backed Israeli anti-govt protests: Leaked Pentagon documents

The president and founder of a German-based think tank, The Schiller Institute, said earlier in April that the Pentagon's leaked documents showed that Washington saw the Ukrainian forces as pawns in a proxy war.

Discrediting Teixeira

In a bid to label Teixeira as a danger to the community, prosecutors said the suspect had "detailed and troubling discussions about violence and murder" on Discord. They also highlighted that he had been suspended during high school when a classmate overheard him discussing Molotov cocktails.

Prosecutors alleged in their filing that Teixeira took steps to destroy evidence after news outlets began reporting on the document leaks.

The New York Times reported earlier in April that soon after the start of the Ukraine war, “a user profile matching that of Airman Jack Teixeira began posting secret intelligence on the Russian war effort on a previously undisclosed chat group on Discord” that contained about 600 members.

The newspaper said it knew about the additional Discord room, which was publicly listed on a YouTube channel and was easily accessed in seconds by a user.