The Massachusetts Air National Guardsman charged with leaking classified military documents was warned several times about his handling of classified information, prosecutors said in a court filing.
Jack Teixeira currently awaits trail after he was arrested last month on charges under the Espionage Act. Federal prosecutors said the former airman was warned by superiors on two occasions last year over “concerning actions” relating to classified information, but continued to leak documents.
“The defendant even continued to share information with his online associates, defying these admonishments and taking further efforts to conceal his unlawful conduct,” prosecutors wrote.
In their court filing, prosecutors cited three memos in which Mr Teixeira was warned.
The first, from September, said Mr Teixeira was told not to take notes on classified information after he was seen putting notes he had written in his pocket. Another from October said one superior was informed that Mr Teixeira was “potentially ignoring the cease-and-desist order on deep diving into intelligence information” given to him.
A third memo found that he viewed information “that was not related to his primary duty and was related to the intelligence field”. Mr Teixeira was not reprimanded at the time.
Lawyers for Mr Teixeira say he should be released on bail, having “peacefully submitted to arrest” after armed tactical agents surrounded his mother's home.
A judge in Massachusetts is expected to rule on Friday whether Mr Teixeira is to remain in custody as the case continues.
The documents appeared to contain detail on Nato support for Ukraine, although their veracity remains unclear.
The leak is thought to be the most serious breach since WikiLeaks in 2010.
Agencies contributed to this report