WASHINGTON (AP) -- After the firefight that killed Osama bin Laden, the U.S. used "multiple methods" to positively identify his remains, according to a senior Pentagon official who personally saw a photograph of the corpse.
The official, who discussed the matter on condition of anonymity because he was not authorized to speak publicly, declined to specify the methods of identification, but two Obama administration officials said DNA evidence confirmed the death.
The officials claimed the DNA evidence provides a match with 99.9 percent confidence.
The officials did not immediately say where or how the testing was done but the test explains why President Barack Obama was confident to announce the death to the world Sunday night. Obama provided no details on the identification process.
The U.S. is believed to have collected DNA samples from bin Laden family members in the years since the 9/11 attacks that triggered the U.S.-led invasion of Afghanistan. It was unclear whether the U.S. also had fingerprints or some other means to identify the body on site.
Bin Laden was shot in the head during the firefight with members of an elite American counter-terrorism unit that launched a helicopter-borne raid on the al-Qaida leader's compound in Pakistan early Monday, U.S. officials said. Officials said the U.S. special forces who stormed the compound came face to face with their prey.
U.S. officials also said bin Laden was identified through "facial recognition," a reference to technology for mapping unique facial characteristics, but it was not clear exactly how the Navy SEAL troops performed the comparison.
The body was later taken to an American warship, but the senior Pentagon official declined to say which one and where the ship was situated.
The body was photographed before being buried at sea, although no images have been released by the Obama administration.
The U.S. official who disclosed the burial at sea said it would have been difficult to find a country willing to accept the remains. Obama said the remains had been handled in accordance with Islamic custom, which requires speedy burial.
Positive identification of the remains is considered a critically important part of the U.S. operation, given the symbolic importance of bin Laden's leadership of the Islamic extremist movement that was based in Afghanistan until the U.S. invaded in October 2001.
When al-Qaida's leader in Iraq, Abu Musab al-Zarqawi, was killed in a U.S. airstrike in June 2006, DNA tests were performed by the FBI to positively identify the remains. The U.S. military also performed an autopsy, in part to dispel allegations in the immediate aftermath of the airstrike that the terrorist leader had been beaten or shot by U.S. soldiers while in American custody.
It was not clear Monday whether the Obama administration intended to release its photos of bin Laden's body.
In July 2003, when U.S. forces killed Saddam Hussein's sons, Odai and Qusai, in a gunbattle in northern Iraq, the U.S. military released graphic after-death photographs in an effort to prove to Iraqis that they were dead. Two of the photos showed the first man, identified as Qusai, with bruises and blood spots around his eyes. That face was far more intact than the other, identified as Odai; the mouth was open with the teeth showing.
Associated Press writers Ben Feller and Matt Apuzzo contributed to this report.
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