Two Metropolitan Police officers are on restricted duties following developments in the Mark Duggan shooting inquiry. The shooting led to the outbreak of rioting in north London over the summer.
It has emerged that the gun found at the scene of Mark Duggan's shooting was used in an alleged assault five days earlier.
The weapon, a BBM Bruni converted handgun, was recovered after a firearms-led Trident operation to arrest Mr Duggan ended in his fatal shooting in Tottenham, North London on 4 August.
Contrary to initial reports, the gun had not been fired but was loaded with one bullet.
The Metropolitan Police announced that a 29-year-old man has been charged with assault and possession of that gun with intent to cause fear of violence at a hairdresser's in Hackney on 29 July 2011.
Kevin Hutchinson, of no fixed address, is also charged with transferring the gun at some time between then and the time it was found where Mark Duggan was shot dead.
The Independent Police Complaints Commission is to carry out the inquiry. It says it is looking at whether the two officers, who have been placed on restrictive duties, could have prevented the gun being handed on.
DNA not on gun
IPCC Commissioner Sarah Green said: "Our investigation will consider whether all investigative lines were promptly identified and acted upon by officers from the Metropolitan Police Service and to what extent, if any, the conduct of this investigation may have impacted on the supply of the firearm found at the scene of the shooting of Mark Duggan."
The Duggan family has yet to release a statement.
Channel 4 News understands there is no trace of Mr Duggan's DNA on the handgun. There are reports that he was carrying it in a sock at the time in order to avoid leaving a forensic trail and to capture any cartridges which were fired.
The shooting led to the riots in Tottenham two nights later.