Investigations carried out by then president Pervez Musharraf's government blamed Baitullah Mehsud, a Pakistani Taliban commander who operates in the lawless tribal areas of northwest region. Central Intelligence Agency (CIA) officials also agreed that Mehsud was the most likely culprit.

London's Scotland Yard was called in to determine whether Bhutto had died because of the gun shot wound or by hitting the sunroof of her vehicle. The British findings in favour of her having hit the sunroof were rejected by her party.

Bhutto's supporters, not satisfied by Pakistani investigations, have hinted that Musharraf and his allies were involved in the murder. When her husband Asif Ali Zardari became president, he asked the UN to carry out an independent investigation.

The commission will perform 'fact finding activities in Pakistan and abroad', according to the office of the UN secretary general.

Its final report will be presented to UN chief Ban Ki-moon within six months. The findings will be shared with the Pakistani government and the Security Council 'for information'.