Al-Qaeda founder Osama bin Laden was spotted by facial recognition software while he was exercising in his Pakistan compound in September, it emerged yesterday.
The breakthrough set in chain a sequence of events which led to his death in a 40-minute operation witnessed by US President Barack Obama via satellite.
US officials revealed that bin Laden's Abbottabad compound had been under surveillance for several months.
And it was facial recognition software that identified bin Laden from satellite pictures as he exercised outside in September.
It also emerged that bin Laden was shot twice in the head and once in the stomach during the raid, which was relayed to Washington via a camera on the helmet of a Navy Seal.
When the death was confirmed, Mr Obama said: "We got him."
Bin Laden was shot first in the left eye by a Seal and, according to reports, was shot a second time in the head and then in the chest to make sure he was dead.
Conflicting reports emerged of whether one of bin Laden's wives was also killed.
US officials first suggested then later denied that she died while being used as a human shield.
In a White House briefing yesterday, US counter-terrorism chief John Brennan said that the US troops could have taken bin Laden alive - but he resisted.
"The concern was that bin Laden would oppose any capture operation," said Mr Brennan.
"Indeed, he did. There was a firefight, he therefore was killed in that firefight.
"He was engaged in a firefight with those that entered the area of the house he was in. Whether or not he got off any rounds I don't know.
"Here is bin Laden, who has been calling for these attacks, living in this million dollar-plus compound ... I think it really just speaks to just how false his narrative has been over the years."
The White House is facing mounting pressure to produce firm evidence that bin Laden is dead.
Officials said the US used multiple means to confirm bin Laden's identity during and after the firefight, before placing his body in the North Arabian Sea from aboard a US aircraft carrier.
The al-Qaeda leader was identified by name by a woman believed to be one of his wives - bin Laden had four - who was present at his Pakistan compound at the time of the American raid.
He was also visually identified by raid squad members, a Pentagon spokesman said.
A DNA match, using DNA from several family members, provided virtual certainty that it was bin Laden's body as well, the spokesman said.
Questions were also being raised over Pakistan's involvement in hiding the al-Qaeda fugitive.
The compound was constructed in 2005 and was near the site of Pakistan's most eminent military academy.
Last night, Pakistan president Asif Ali Zardari denied suggestions his country's security forces had sheltered bin Laden.
Mr Zardari said: "Some in the US press have suggested that Pakistan lacked vitality in its pursuit of terrorism, or worse yet that we were disingenuous and actually protected the terrorists we claimed to be pursuing.
"Such baseless speculation may make exciting cable news, but it doesn't reflect fact."