USIS declined to comment on whether it conducted a background investigation of Snowden. "These investigations are confidential and USIS does not comment on them," the company said.
The background check USIS performed on Snowden was done in 2011 and was part of periodic reinvestigations that are required for employees who hold security clearances, according to McFarland and Michelle Schmitz, the assistant inspector general for investigations at OPM.
Schmitz said the investigation of USIS commenced later in 2011.
The new documents revealed by The Guardian were signed by Attorney General Eric Holder. They include point-by-point directions on how an NSA employee must work to determine that a person being targeted has not entered the United States. If NSA finds the target has entered the U.S., it will stop gathering phone and Internet data immediately, the documents say.
If supervisors determine that information on a U.S. person or a target who entered the U.S. was intentionally targeted, that information is destroyed, according to the documents.
But if a foreign target has conversations with an American or a U.S.-based person whom NSA supervisors determine is related to terrorism, or contains significant intelligence or evidence of crimes, that call or email or text message can be kept indefinitely. Encrypted communications also can be kept indefinitely, according the documents.
Administration officials had said the U.S. phone records NSA gathered could only be kept for five years. A fact sheet those officials provided to reporters mentioned no exceptions.
The documents outline fairly broad authority when the NSA monitors a foreigner's communications. For instance, if the monitored foreigner has been criminally indicted in the U.S. and is speaking to legal counsel, NSA has to cease monitoring the call. The agency, however, can log the call and mine it later so long as conversation protected by attorney-client privilege is not used in legal proceedings against the foreigner.
The NSA had no comment when asked about the newly revealed documents.