Contested cause
After the assassination, government officials asserted that Bhutto died by hitting her head against a sunroof handle in the car she was travelling in, but her party and many Pakistanis did not accept that explanation.
A poll conducted by Gallup Pakistan found almost half of all Pakistanis believed government agencies or politicians allied to Musharraf were involved in the assassination.
Bhutto's aides say they saw bullet wounds on her head as they bathed her corpse before burial. They have also criticised Pakistani authorities for washing the scene hours after the attack.
The British team of forensics and other experts spent two and a half weeks in Pakistan in January at the invitation of Pervez Musharraf, the Pakistani president.
No autopsy was carried out, at the request of Bhutto's family. Scotland Yard detectives only investigated how Bhutto was killed, not who was behind it.
The British team said its task was complicated by the "lack of an extended and detailed search of the crime scene, the absence of an autopsy, and the absence of recognised body recovery and victim identification processes."
But it said that there was sufficient evidence to draw "reliable conclusions", including X-rays checked against Bhutto's dental records and video footage taken by witnesses.
The report comes less than two weeks before Pakistan's parliamentary elections on February 18, which were delayed because of Bhutto's assassination.
As thousands gathered on Thursday to mark the end of a 40-day mourning period for the former prime minister, Pakistani authorities announced two "important arrests" in connection with her assassination.
A senior police officer in Rawalpindi identified the suspects as Hasnain and Rifaqat, but gave no other details.
Two other people, including a 15-year-old who admitted being a backup suicide bomber, were arrested last month.