Detectives investigating Britain's biggest jewellery heist have recovered a loaded firearm, Scotland Yard said.
Police also released more details of the getaway cars and said the robbers used cloned number plates.
The two men fired a gun as they escaped with 43 items of jewellery from Graff Jewellers on New Bond Street in London's West End last Thursday.
But the gun officers have recovered is not believed to be the one fired during the incident.
The men abandoned a blue BMW in a nearby street after it hit a black taxi just seconds after the raid.
Officers have also found a high-powered motorbike possibly used to spirit away a bag holding the stolen gems.
A second shot was fired as the robbers got into a silver Mercedes in nearby Dover Street and were challenged by drinkers at a pub.
The car drove on into Farm Street where it is believed some of the suspects got into another car.
Scotland Yard described the first vehicle as a silver B-class Mercedes with the registration number LV06 HFA.
The second vehicle was described as a blue Volkswagen Sharan with the registration number RA07 XEV.
A police spokesman said the registration plates were known to be cloned.
Officers arrested and questioned a 50-year-old man in Ilford, east London, on Monday in connection with the robbery.
They suspect that the man, who has been released on bail, may have been involved in planning the raid, although he was not in the West End when it took place.
Officers have searched at least three properties in a series of raids across London and the South East.Reuse content