ABC News April 15, 2023

Why document leak suspect Jack Teixeira had a high-level top secret security clearance

WATCH: Alleged military leak suspect in court

Jack Teixeira, the 21-year-old junior enlisted airman with the Massachusetts Air National Guard, who has been charged as being behind the leak of classified U.S. military and U.S. intelligence documents had a high-level top security clearance that raises even more questions about why he had access to such documents in his work as an IT specialist.

The criminal complaint against Jack Teixeira released Friday disclosed that he possessed a high-level top secret clearance known as TS-SCI, Top Secret - Sensitive Compartmented Information, since 2021.

Teixeira worked as a full time active-duty Air National Guardsman at Otis Air National Guard Base, near Cape Cod, Massachusetts, as a "Cyber Transport Systems Journeyman" -- essentially providing IT support for the 102nd Intelligence Wing.

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Suspected classified document leaker and U.S National Guardsman, Jack Teixeira, is taken into custody by FBI agents in North Dighton, Mass., April 13, 2023.

Defense officials told ABC News that having a TS-SCI clearance is typical for Air Force personnel who in order to provide IT support might need access to classified spaces, computers and networks so they could do their jobs.

But the fact that you have a clearance does not mean you have access to everything at that level. That access is based on your "need to know" the information for your job.

MORE: Suspect in classified documents leak makes 1st court appearance

That term refers to someone with a security clearance who is allowed to see certain levels of classified documents only if they "need to know" that information to carry out their jobs.

To service the computers and networks he worked on, Teixeira would've had access to highly sensitive networks, but if he wanted to access highly classified documents on that network for his job he could do so only if he had that clearance.

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Suspected classified document leaker and U.S National Guardsman, Jack Teixeira, is taken into custody by FBI agents in North Dighton, Mass., April 13, 2023.

The "need to know" status is standard across the U.S. military and U.S. intelligence and means a top security clearance is not enough to be able to view specific intelligence documents.

The criminal complaint provides a description of how investigators used information from an unnamed U.S. government agency that "has access to logs of certain documents" to track how Teixeira allegedly used his clearance in February to look for a specific document that he later posted on a small Discord channel the following day.

MORE: Discord admins describe 'hyperactive kid' who they say helped spread images of classified docs

Another logging system from another U.S. government agency that "can monitor certain searches conducted on its classified networks" indicated that Teixeira may have been concerned about the initial news reports that classified intelligence documents had begun to appear on Twitter and Telegram.

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This image made from video provided by WCVB-TV, shows Jack Teixeira, in T-shirt and shorts, being taken into custody by armed tactical agents on April 13, 2023, in Dighton, Mass.

Teixeira on April 6 "used his government computer to search classified intelligence reporting for the word 'leak,'" according to the complaint.

"The first public reporting regarding the Government Information appeared on or around April 6, 2023," it added. "Accordingly, there is reason to believe that TEIXEIRA was searching for classified reporting regarding the U.S. Intelligence Community's assessment of the identity of the individual who transmitted classified national defense information, to include the Government Document."

Teixeira, who was arrested without incident at a residence in North Dighton, Massachusetts, on Thursday, has yet to enter a plea to the charges.