U.S. investigators have concluded that former national security contractor Edward Snowden collected some of the huge cache of surveillance documents he has disclosed by copying the password of a coworker who since has resigned.
Snowden has said that he did not steal the secure passwords of colleagues at the National Security Agency outpost where he worked on the Pacific island U.S. state of Hawaii. But the NSA said in a memo to a congressional panel this week that at Snowden's request, a civilian NSA worker allowed the contractor to use his encrypted digital key on Snowden's computer.
The NSA memo said Snowden then was able to capture the password, giving him even greater access to classified information on the agency's computer network.
The agency said the coworker acknowledged the security breach last June, but was not aware that Snowden planned to leak details about the extensive U.S. surveillance programs.
The clandestine spy agency said it revoked the coworker's security clearance, and he resigned last month after the NSA said it planned to fire him.
The NSA memo said an active duty member of the military and a private contractor also had their security access restricted as part of the continuing investigation of what officials say is one of the biggest U.S. security breaches ever.
NSA officials say that Snowden stole 1.7 million documents about U.S. spy programs, leaking many of them to journalists who have written numerous stories over the last several months about the surveillance.
The 30-year-old Snowden is living in asylum in Russia. American authorities have been unsuccessful in their efforts to extradite him to stand trial on espionage charges in the United States.