U.S. May Never Know Full Extent of Snowden's Spy Revelations, Say Officials

Keep 'em guessing

WASHINGTON — American intelligence and law enforcement investigators have concluded that they may never know the entirety of what the former National Security Agency contractor Edward J. Snowden extracted from classified government computers before leaving the United States, according to senior government officials.

Investigators remain in the dark about the extent of the data breach partly because the N.S.A. facility in Hawaii where Mr. Snowden worked — unlike other N.S.A. facilities — was not equipped with up-to-date software that allows the spy agency to monitor which corners of its vast computer landscape its employees are navigating at any given time.