Trail that led from Guantanamo to a $1m compound in Pakistan

At just after 1.15 in the morning, residents of Abbottabad were woken by shattering explosions. Prolonged bursts of gunfire followed and military vehicles hurtled towards a building in flames in a wealthy neighbourhood on the edge of the city.

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A little later, the silhouettes of three helicopters could be seen rising and disappearing into the dark sky. A decade after 9/11, the hunt for Osama bin Laden was finally over.

The operation which claimed the life of the founder of al-Qa'ida, and the world's most wanted terrorist, had taken only 48 minutes. Bin Laden had been shot dead. Four others, including a woman, were also killed. A helicopter which had crashed at the site was blown up by the departing US special forces as they flew off with the bodies.

There had been a brief but fierce firefight with guards on the roof of the house opening up with Kalashnikov assault rifles and rocket-propelled grenades. The downed helicopter may have been damaged in this exchange. Bin Laden was shot twice in the head, his death likely to be viewed as an "execution" after it emerged Barack Obama had sanctioned a "kill option" to the US Navy Seals.

Bin Laden's heavily fortified last refuge was only 100 yards from Pakistan's version of Sandhurst, the Kakul Academy, in a city bristling with security facilities. US officials had little doubt that senior elements within the country's military and intelligence service had been shielding the al-Qa'ida leader, and had taken every precaution possible to ensure they did not learn how close the Americans were to getting their quarry.

The trail that led to the deaths at Abbottabad started six years ago when two detainees at Guantanamo Bay had provided the nickname for Bin Laden's most trusted courier, a protégé of Khalid Sheikh Mohammed. It took another 12 months to find the man's real name, and it was not until 2009 that it emerged he was based close to Islamabad.

The fact the courier was operating with seeming impunity near the Pakistani capital convinced US officials he had the protection of the ISI, the Pakistani secret police, and reinforced their decision not to share their information with the Pakistanis.

Investigations, mainly reliant on electronic tracking, eventually led them to a residence the courier shared with his brother at Abbottabad. The mansion, set on a hilltop, ringed by 12ft-high reinforced concrete walls topped with razor wire, had been built in 2005 at a cost of $1m, 10 times more than other properties in the area. It did not, however, have either telephone or internet connection – seen as a counter-surveillance measure.

The CIA was convinced the location was for the use of someone extremely important and, for a while, explored the possibility it might be housing Mullah Omar, the former head of Afghanistan's Taliban regime, who the ISI is thought to have moved from Pakistan's border areas to save him from possible American drone strikes.

However, after a month's further investigation Leon Panetta, the head of the CIA, told the President the agency believed it was, in fact, Bin Laden who was staying in the compound. It was decided the Pakistani authorities should be given every opportunity to disclose any knowledge of the al-Qa'ida leader's whereabouts. But the ISI and the Pakistani military insisted, as they had done in the past, that Bin Laden was either dead or in Afghanistan.

In the meantime, Umar Patek, an Indonesian link man with al-Qa'ida, who had made contact with Bin Laden's courier, was arrested by Pakistani officials in Abbottabad. The house where Bin Laden was staying was not, however, searched during the investigation into the activities of the Indonesian.

Two more months of surveillance followed before Mr Obama held the first of five meetings with the National Security Council on 14 March.

The last session took place at 8.20am last Friday at the Diplomatic Room at the White House when, before flying off to inspect flood damage in Alabama, President Obama finally authorised the operation.

The President spent part of Sunday playing golf before he returned to review final preparations for the raid. It began when a special forces squad, the Navy's elite Seal Team Six, took off from the Ghazi airbase in north-west Pakistan, where it had been on standby. They returned in the early hours of the morning with Bin Laden's corpse, which was transferred to another aircraft heading for Afghanistan.

There, at Bagram airbase, the formalities of identification were concluded, and the man who had been projected as the most dangerous enemy facing the West, was taken on his final journey for burial at sea.