The U.S. government only searched for detailed information on calls involving fewer than 300 specific phone numbers among the millions of raw phone records collected by the National Security Agency in 2012, according to a government paper obtained by Reuters on Saturday.
The unclassified paper was circulated Saturday within the government by U.S. intelligence agencies and apparently is an attempt by spy agencies and the Obama administration to rebut accusations that it overreached in investigating potential militant plots.
The administration has said that even though the NSA, according to top-secret documents made public by former agency contractor Edward Snowden, collects massive amounts of data on message traffic from both U.S. based telephone and internet companies, such data collection is legal, subject to tight controls and does not intrude on the privacy of ordinary Americans.
The paper circulated on Saturday said that data from the NSA phone and email collections programs not only led U.S. investigators to the ringleader of a plot to attack New York's subway system in 2009, but also to one of his co-conspirators in the United States.
The paper discusses an NSA program that collects "metadata" - raw information that does not identify individual telephone subscribers - from major U.S. phone companies showing all calls made by those companies' subscribers to phones within the United States and overseas.
It also mentions another NSA program, called Prism in leaked documents, that collects from internet companies what the paper says are emails of foreigners who might be of interest to counterterrorism or counter-proliferation investigators.
Millions of phone records were collected in 2012, but the paper says U.S. authorities only looked in detail at the records linked to fewer than 300 phone numbers.
A person familiar with details of the program said the figure of fewer than 300 numbers applied to the entire mass of raw telephone "metadata" collected last year by the NSA from U.S. carriers - not just to Verizon, which is the only telephone company identified in a document disclosed by Snowden as providing such data to the NSA.
The paper repeats assertions by administration spokesmen that NSA email and telephone data-collection programs contributed to the disruption of "dozens of potential terrorist plots here in the homeland and in more than 20 countries around the world."
The paper says NSA collection of email and telephone data helped U.S. authorities track down Najibullah Zazi, an Afghan immigrant who in 2009 was arrested for plotting to bomb the New York City subway system. Zazi pleaded guilty to terrorism charges.
NSA monitoring of the email of alleged al Qaeda operatives in Pakistan led them to an unnamed person in the United States who was making "efforts to procure explosive material," according to the government paper. The NSA gave its raw information to the FBI, which identified Zazi, who was then living in Colorado. After tailing him to New York, the FBI arrested him.
By cross-checking Zazi's phone number with its giant data base of raw phone traffic, the paper said more leads were generated for the FBI. One of those leads took authorities to Adis Medunjanin, who was convicted last year in the subway plot and sentenced to life in prison.