Massachusetts Air National Guard member Jack Teixeira was sentenced to 15 years in federal prison for violating the Espionage Act. He pleaded guilty to leaking information about the war in Ukraine.

Teixeira pleaded guilty in March to six counts of willfully retaining and transmitting national defense information.

Prosecutors said Jack Teixeira "perpetrated one of the most significant and consequential violations of the Espionage Act in American history."

Teixeira pleaded guilty in March to six counts of leaking classified military information. His plea deal included 16 years in prison.

Pentagon leaker Jack Teixeira will now face a military court-martial, according to the U.S. Air Force.

Air Force prosecutors asked to recommend that Jack Teixeira be court-martialed for disobeying orders and obstructing justice after leaking national defense secrets.

Massachusetts Air National Guardsman Jack Teixeira will face military criminal proceedings this month for alleged violations of the Uniform Code of Military Justice.

According to the signed plea agreement filed with the court, Teixeira agreed to plead guilty to all six counts charging him with willful retention and transmission of national defense information.

Teixeira was accused of leaking a trove of classified military documents and posting them online.

ABC News Senior Investigative Reporter Aaron Katersky gives insight into why Teixeira changed his plea and what to expect in court Monday.

Jack Teixeira, the young Massachusetts Air National Guardsman accused of leaking a trove of classified military documents, is pleading guilty.

The airmen have been disciplined for failing to take proper action when they became aware of Teixeira's intelligence-seeking activities, according to a report.

Fifteen airmen have been disciplined for failing to take proper action when they became aware of accused leaker Jack Teixeira's activities, the Air Force said

The service members failed to take proper action after they became aware of accused leaker Jack Teixeira’s intelligence-seeking activities, according to an Air Force investigation.

The Massachusetts Air National Guardsman accused of posting classified information on an online chat group asked a federal judge to reconsider his pretrial detention.

The Pentagon will tighten controls on classified information after the Discord leak.

Air National Guardsman Jack Teixeira allegedly leaked classified documents to friends on Discord.

Jack Teixeira pleaded not guilty Wednesday to six counts of willful retention and transmission of national defense information.

Jack Teixeira now faces six counts of willful retention and transmission of classified information and is awaiting a new court date.

The 10-page indictment accused Jack Teixeira of willful retention and transmission of national defense information.

Jack Teixeira, the member of the Massachusetts Air National Guard accused of leaking classified documents online, has been indicted by a federal grand jury.

The Special Counsel has expanded his probe into political action committees that were formed by Trump allies.

The judge ruled Jack Teixeira, the Air National Guardsman suspected of leaking classified documents, should be held without bail until his trial.

Jack Teixeira, the 21-year-old airman charged in connection with the leaked documents probe, was ordered detained ahead of his trial during a hearing Friday.

A federal judge rejected the appeal for the pre-trial release of an Air National Guardsman charged with leaking defense secrets.

Jack Teixeira, the 21-year-old airman charged in connection with the leaked documents probe, was ordered detained ahead of his trial during a hearing Friday.

Plus, details on what is holding up critical debt ceiling negotiations, and how one South Carolina lawmaker worked to ban sexual extortion scams after his son’s tragedy.

ABC News' Aaron Katersky joins ABC News contributor Mick Mulroy to break down the case against Jack Teixeira, the Air National Guardsman accused of leaking classified documents.

Federal prosecutors say releasing Jack Teixeira, an Air National guard member accused of leaking America's defense secrets, poses too great a risk to public safety and national security.

Jack Teixeira faced multiple reprimands for "willful disregard" in protecting classified information, federal prosecutors said in a court filing.

According to new court papers, Jack Teixeira, the 21-year-old alleged leaker, was caught taking notes on classified documents.

Jack Teixeira was twice admonished by his superiors last year over his "concerning actions" with regards to classified information, prosecutors said in a court filing

Prosecutors claim that the Pentagon leak suspect was warned of his “concerning actions” with classified information.

Prosecutors say the former National Guardsman was allowed to keep his security clearance despite having been caught mishandling classified documents multiple times. ABC News’ Justin Finch reports.

The 21-year-old National Guardsman will face a judge Thursday and is accused of leaking classified Pentagon documents online.

Prosecutors say Jack Teixeira is a flight risk and could still have access to sensitive intelligence as a judge decides whether to release him on bail.

ABC News' Trevor Ault provides updates outside of the courthouse in Worcester, Massachusetts, as prosecutors argue Jack Teixeira is a flight risk.

Federal prosecutors argued in a filing Jack Teixiera, 21, "must remain detained" as he “poses a serious flight risk."

A judge is reviewing a request by the Massachusetts airman who federal prosecutors contend stole and leaked classified documents.

A federal judge is weighing a possible pre-trial release for alleged Pentagon leaker Jack Teixeira, while prosecutors argue he’s a flight and national security risk.

The Massachusetts airman accused of leaking highly classified U.S. intelligence documents is asking a magistrate judge to release him from pretrial detention.

Massachusetts Air National Guardsman Jack Teixeira accessed "hundreds" of highly classified U.S. intelligence documents, federal prosecutors said.

Reports have indicated suspect Jack Teixeira was driven to share classified documents to impress friends he made on the messenger platform Discord.

A lawyer for Jack Teixeira had asked the judge for more time to prepare his case.

The judge overseeing Jack Teixiera's case granted the former National Air Guardsman's request to delay his detention hearing on Wednesday.

Jack Teixera, 21, is charged with unauthorized retention and transmission of national defense information and willful retention of classified documents.

Jack Teixeira, 21, "improperly and unlawfully retained and transmitted national defense information to people not authorized to receive it."

Jack Teixeira, 21, "improperly and unlawfully retained and transmitted national defense information to people not authorized to receive it."

The Air Force has opened its own probe into the secret documents disclosure and says the accused leaker’s unit is no longer carrying out its intelligence mission.

The Pentagon said it's working around the clock to understand the scope and scale of the leak of classified documents.