The operation that led to the killing of the world's most-wanted terrorist Osama Bin-Laden was almost nine-month old but surprised the world over its ease and success, due to the crucial role played by the intelligence agencies.

Pakistan maintained that Osama bin-Laden was not in the country, despite reports to contrary since 2001.

Here is how the operation was planned:

Aug. 2010: The U.S. administration gets an intelligence lead that Laden was in Pakistan and the venue was not confirmed. President Obama gives a go-ahead in pursuit of the lead to reach Osama bin-Lade.

April last week: Obama authorizes mission to storm a house in Abbottabad military cantonment area which was believed to be holding a top terrorist. US intelligence officials zero-in on Laden as the person living in the building and go ahead.

VENUE: A large, 10-year-old, three-storey mansion was built by a Pashtun man in the compound of Abbottabad's military cantonment, in an area measuring about 3,000 sq yards that suited a perfect refuge to a man like bin Laden.

It had 14 feet high concrete walls around the compound and not many people in the neighborhood were unaware as to who stayed there. It had no telephone or Internet lines going into the compound and the area known as Tanda Choha, 80 miles off Islamabad, had housed high-ranking military officers with frequent checkpoints.

It is 800 yards from the Pakistan Military Academy where the elite military cadets are trained the way Britain's Sandhurst military training academy, a colonial legacy that continued after Pakistan's independence in 1947.

US troops, operating out of a base in Tarbela Ghazi, an area close to Abbottabad, took off in three helicopters and landed outside the compound at about 2230 local time (1730GMT) and the operation lasted for about 45 minutes.

OPERATION: The day began with house-to-house search in the area. Soon after landing in front of the compound, US troops began to spread out immediately, telling local residents in Pashtu language to switch off their lights and remain inside until further orders. Others enter the compound and next 45 minutes saw exchange of firing inside the building.

One of the helicopters hovering over the building was shot down by firing from inside the compound and a family member was killed in the incident though the pilot escaped. One report says he was killed in head and one of his sons was also killed in the incident.

OUTCOME: US troops finally kill Osama bin-Laden and capture his wife and emerge out of the compound.

ON TWITTER: Akhtar, who runs a coffee shop in Abbottabad, was among the first to tweet about the incident to the world almost eight hours before President Obama did. Helicopter hovering above Abbottabad at 1AM, said his first tweet, followed by other tweets on fire and blockades in the area.