US authorities had in their possession two separate sets of evidence indicating that the hostage Linda Norgrove may have been killed by US troops rather than by her kidnappers, as they at first claimed.
The official version initially given, that her death was due to a suicide vest, was called into doubt by film from troops' helmet cameras and a second set of footage taken from an aircraft overhead. Both revealed a soldier throwing a grenade towards the corner of a building in Afghanistan where the 36-year-old aid worker was being held.
It has also emerged that Ms Norgrove was still alive when the soldiers got to her — an unlikely scenario if, as was being claimed, she had been right next to an exploding bomb.
Nato officials yesterday admitted that it had been a major mistake to state so categorically that the Briton had been murdered by one of her Taliban abductors. “Nothing so definite should have been put out,” an official said.
Ms Norgrove was killed on Saturday when the mission to free her went disastrously wrong.