Exclusive: Inside Account of U.S. Eavesdropping on Americans

The NSA: "The Shadow Factory"

Both former intercept operators came forward at first to speak with investigative journalist Jim Bamford for a book on the NSA, "The Shadow Factory," to be published next week.

"It's extremely rare," said Bamford, who has written two previous books on the NSA, including the landmark "Puzzle Palace" which first revealed the existence of the super secret spy agency.

"Both of them felt that what they were doing was illegal and improper, and immoral, and it shouldn't be done, and that's what forces whistleblowers."

WATCH Bamford describe how the NSA missed signals leading up to 9/11.

A spokesman for General Hayden, Mark Mansfield, said: "At NSA, the law was followed assiduously. The notion that General Hayden sanctioned or tolerated illegalities of any sort is ridiculous on its face."

The director of the NSA, Lt. General Keith B. Alexander, declined to directly answer any of the allegations made by the whistleblowers.

In a written statement, Gen. Alexander said: "We have been entrusted to protect and defend the nation with integrity, accountability, and respect for the law. As Americans, we take this obligation seriously. Our employees work tirelessly for the good of the nation, and serve this country proudly."

Click Here for the Investigative Homepage.