"The police shooting victim whose death sparked the riots did not fire at officers before he was killed, ballistic tests indicate.
There is "no evidence" that a handgun found at the scene where Mark Duggan was killed by armed officers was used, the Independent Police Complaints Commission (IPCC) said.
The 29-year-old's death, after receiving a gunshot wound to the chest last Thursday, was a trigger for the first night's rioting in Tottenham on Saturday.
Mr Duggan's death came after two shots were fired by a Scotland Yard CO19 firearms officer, investigations show.