Ethel Rosenberg

Jack Teixeira faces a lengthy Prison sentence if convicted of involvement in what The Pentagon has deemed a " very serious" National Security risk, experts have said.

The 21-year-old military cyber-specialist is suspected of leaking sensitive US documents.

The Pentagon said it believes the leak was a deliberate criminal act.

Mr Teixeira is expected to make his first appearance In Court on Friday in Boston.

He is a member of The Intelligence wing of the Massachusetts Air National Guard .

Merrick Garland , the US Attorney General , said Mr Teixeira faced charges under the 1917 Espionage Act.

Steven Stransky, an attorney who previously served as senior counsel to The Department of Homeland Security 's Intelligence Law Division, said The Act was " very old and outdated" and " essentially criminalises an individual collection, disclosure or potentially re-disclosure, of national defence information".

He added that while the term " national defence information" is only vaguely defined in The Law , it broadly means information that " can injure the United States or put us at a disadvantage vis-a-vis another third country".

Several spies and people who have shared Classified Information with The Press and The Public have been charged since The Law was first enacted in 1917, albeit infrequently.

It has historically largely been applied to Americans found spying for foreign countries, such as Julius and Ethel Rosenberg , who were executed in 1953 after being found guilty of passing nuclear secrets to the Soviet Union . The Espionage Act authorised the death penalty for espionage " In Time of war" - and at The Time , the US was involved in the Korean War .

More recently, the Espionage Act has been applied to whistleblowers and people who have leaked sensitive information, including Wikileaks source Chelsea Manning and ex-CIA contractor Edward Snowden .

This will depend on the charges Mr Teixeira will face.

When the Espionage Act was originally passed, it stipulated Prison sentences of 20 years or less and fines of up to $10,000 per charge.

Reuters news agency quoted Brandon Van Grack, a former Justice Department National Security prosecutor now with the Law Firm Morrison Foerster, as saying the likely charges could carry up to 10 Years ' imprisonment, even if Mr Teixeira did not intend to cause harm.

" This is someone who is facing on The Higher end of exposure for years in Prison . . because the leaks were so damaging, " Mr Van Grack said.

" There's certainly criminal charges that could attach to it [the Espionage Act] and there's financial penalties as well, " Mr Stransky said. " If the justice department is pursuing a criminal violation for the Espionage Act, they're most often looking for jail sentencing as a way to deter these types of future actions. "

The Pentagon press secretary indicated it would treat the leak extremely seriously, saying it was " a deliberate criminal act". A Pentagon spokesperson said that " stringent" guidelines were in place for employees and that " anyone who violates those rules is doing so wilfully".

Source of news: bbc.com