Benazir Bhutto died of a "severe head injury" and not a gunshot wound in an attack by a lone terrorist, Scotland Yard said today.
British detectives investigating the death of the former Pakistani prime minister have presented their report to the Pakistani authorities, which was released by the Foreign Office today.
The report concluded that Ms Bhutto's only apparent injury was a major trauma to the right side of the head, caused by hitting the escape hatch to her vehicle and not by a gunshot wound. All the evidence suggested a lone attacker fired the shots before blowing himself up.
Ms Bhutto died in an attack during a political rally in Rawalpindi on 27 December.
A report from Home Office pathologist Dr Nathaniel Cary said: "The only tenable cause for the rapidly fatal head injury in this case is that it occurred as the result of impact due to the effects of the bomb blast."
It added: "In my opinion, Mohtarma Benazir Bhutto died as a result of a severe head injury sustained as a consequence of the bomb blast and due to head impact somewhere in the escape hatch of the vehicle."
The report said the only X-rays taken after the death were of Ms Bhutto's head. There was no post mortem and no CT scan.
But the pathologist concluded that a shot to the mid or lower body would have been impossible because of the armoured vehicle in which she was travelling.
A shot to the upper body or neck could not be ruled out, but given the evidence of family and hospital staff who examined the body, this was unlikely, the report said.
And given the severity of the head injury, a shot to the body or neck would not have been a "relevant factor" in the cause of death.
A team from the Metropolitan Police was invited to Pakistan in January by the authorities because of the controversy about how Ms Bhutto died.
The team, led by Detective Superintendent John MacBrayne, delivered its report to interim interior minister Hamid Nawaz.
Despite speculation that two people were involved in the attack - a gunman and a suicide bomber - the report said all available evidence suggested it was the same person.
The body parts of only one individual remain unidentified, and police believe this is the suicide bomber.
Television footage combined with the findings of the forensic explosive expert, place the gunman and the bomber in the same position, only a few yards to the rear of the vehicle.
Anyone in such a position could not conceivably have survived, the report said.
The report concludes: "In essence, all the evidence indicates that one suspect has fired the shots before detonating an improvised explosive device.
"At the time of the attack this person was standing close to the rear of Ms Bhutto's vehicle.
"The blast caused a violent collision between her head and the escape hatch area of the vehicle, causing a severe and fatal head injury."
The report, released through the British High Commission in Islamabad, said the wider investigation to establish culpability remained entirely a matter for the Pakistani authorities.
Mr MacBrayne said the investigation was complicated by the lack of an extended search of the crime scene, the lack of a post mortem, and the lack of a victim identification process.
But he said the available evidence was sufficient for reliable conclusions to be drawn.