Federal prosecutors June 14 charged Snowden, believed to be in Hong Kong, with one count of theft of government property and two counts of giving national defense information to someone without a security clearance and revealing classified information about "communications intelligence," NBC News reported Friday.
He faces a maximum of 30 years in prison.
The U.S. government also has filed a "provisional arrest warrant" seeking Snowden's arrest in Hong Kong and his eventual extradition to the United States.
Snowden worked for contractor Booz Allen Hamilton when he provided details to Britain's The Guardian newspaper and The Washington Post about the NSA's phone and Internet surveillance programs.
A probe of the background check performed on Snowden may itself have been faulty, a government inspector general told lawmakers earlier
"We do believe that there may be some problems" with the reinvestigation of Snowden's background check, Office of Personnel Management Inspector General Patrick McFarland told a Senate panel when asked by Sen. Jon Tester, D-Mont., if he had concerns the background-check reinvestigation wasn't carried out appropriately.
McFarland did not elaborate on what the problems might have been.
But he said his office was investigating U.S. Investigative Services, a company that handles nearly half of the U.S. government's contracted background checks, for contract fraud.
The company conducted the reinvestigation into Snowden in 2011, he said.
USIS, which calls itself "the leader in federal background investigations," said in a statement it received a subpoena for records from McFarland's office in January 2012.
It said it "has cooperated fully" with the government's civil investigation but said it has not been told it is under criminal investigation.
USIS would not comment on whether it conducted any investigations into Snowden, saying those investigations are confidential and under investigation, the Federal Times publication reported.
Snowden fled his base in Hawaii for Hong Kong last month and then leaked the NSA information.
Booz Allen has said it "will work closely with our clients and authorities in their investigation of this matter."
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