Detectives investigating the poisoning of two people in the United Kingdom believe the source of the nerve agent was a small bottle found in one of the victim's house in Amesbury, Scotland Yard said.
The Metropolitan Police said a bottle found at Charlie Rowley's house had been tested by scientists at the Defence, Science and Technology Laboratory (DSTL) at Porton Down.
Mr Rowley remains in hospital but has been able to speak to police.
Dawn Sturgess, 44, and Charlie Rowley, 45, were sickened on June 30 in a town not far from the city where British authorities said a Russian ex-spy and his daughter were poisoned with Novichok in March.
"On Wednesday. a small bottle was recovered during searches of Charlie Rowley's house in Amesbury", police said in a statement. They were found to have been poisoned with Novichok, a lethal nerve agent produced in the Soviet Union during the Cold War. Sturgess died in a hospital on Sunday.
"Scientists have now confirmed to us that the substance contained within the bottle is Novichok".
Further tests are also being carried out to see if the Novichok came from the same batch that was applied to the front door of Skripal's house in Salisbury.
On Tuesday evening, military staff in Hazmat suits seized a white Audi belonging to an Air Ambulance paramedic who treated Ms Sturgess, and wrapped it in clingfilm.
Assistant Commissioner Neil Basu, Head of UK Counter Terrorism Policing, said: "This is clearly a significant and positive development".
"We want to make it clear that there is no cordon in place and once the vehicle has been removed, police will leave the scene and it will be open to the public as normal".