Washington; A fleet of satellites aimed dozens of receivers over Pakistan to collect "critical" information that prepared the ground for the US Navy SEALs raid that killed Osama bin Laden, a media report said on Friday.
Top-secret documents provided to The Washington Post by former NSA contractor Edward Snowden, make brief references to the bin Laden operation.
The disclosures about the hunt for the elusive founder of al Qaeda are contained in classified documents that detail the fiscal 2013 "black budget" for US intelligence agencies, including the NSA and the CIA.
The National Security Agency was able to penetrate guarded communications among al Qaeda operatives by tracking calls from mobile phones identified by specific calling patterns, the budget shows.
Analysts from the CIA pinpointed the geographic location of one of the phones and linked it to the compound in Abbottabad, Pakistan, where other evidence suggested bin Laden was hiding.
The budget reveals that satellites operated by the National Reconnaissance Office performed more than 387 "collects" of high-resolution and infrared images of the Abbottabad compound in the month before the raid, intelligence that was "critical to prepare for the mission and contributed to the decision to approve execution."
Eight hours after the raid, according to the documents, a forensic intelligence laboratory run by the Defense Intelligence Agency in Afghanistan had analysed DNA from bin Laden`s corpse and "provided a conclusive match" confirming his identity.
Also playing a role in the search for bin Laden was an arm of the NSA known as the Tailored Access Operations group.
Among other functions, the group specialises in surreptitiously installing spyware and tracking devices on targeted computers and mobile-phone networks.
Although the budget does not provide detail, it reports that Tailored Access Operations "implants" enabled the NSA to collect intelligence from mobile phones that were used by al Qaeda operatives and other "persons of interest" in the hunt for bin Laden.
Separately, Tailored Access Operations capabilities were used in April 2011, the month before bin Laden was killed, when US forces in Afghanistan relied on signals intelligence from implants to capture 40 low- and mid-level Taliban fighters and other insurgents in that country, according to the documents.
In addition to the satellites, the government flew an advanced stealth drone, the RQ-170, over Pakistan to eavesdrop on electronic transmissions.