Novichok that poisoned a couple in Wiltshire came from a small bottle found in the home of one of the victims, said British police on Friday.
From Scotland Yard, the results of an investigation into a second Russian nerve agent attack on British soil that killed one and gravely sickened a man who remains hospitalized:
UPDATE: Source of nerve agent contamination identified
Counter terrorism detectives investigating the contamination of two people by the nerve agent Novichok believe they have found the source of the deadly substance.
Dawn Sturgess, 44, from Durrington, died in hospital on Sunday evening (8 July) having been exposed to the nerve agent. Detectives launched a murder inquiry following her death.
A post-mortem is scheduled to take place on Tuesday, 17 July and an inquest into Dawn's death is set to open and adjourn in Salisbury at 11:00hrs on Thursday, 19 July.
Her partner, 45-year-old Charlie Rowley, was also taken to hospital critically ill but has since regained consciousness. Charlie remains in a serious, but stable condition as hospital staff continue to work hard to provide the care that he needs.
On Wednesday, 11 July, a small bottle was recovered during searches of Charlie Rowley's house in Amesbury.
It was taken to the Defence, Science and Technology Laboratory (DSTL) at Porton Down, Wiltshire, for tests.
Following those tests, scientists have now confirmed to us that the substance contained within the bottle is Novichok. Further scientific tests will be carried out to try and establish whether it is from the same batch that contaminated Sergei and Yulia Skripal in March – this remains a main line of enquiry for police.
Inquiries are under way to establish where the bottle came from and how it came to be in Charlie's house.
Assistant Commissioner Neil Basu, Head of UK Counter Terrorism Policing, said: "This is clearly a significant and positive development. However, we cannot guarantee that there isn't any more of the substance left and cordons will remain in place for some considerable time. This is to allow thorough searches to continue as a precautionary measure for public safety and to assist the investigation team.
"I also appreciate there is a lot of interest in this; however, we are not in a position to disclose any further details regarding the bottle at this stage.
"The safety of the public and our officers remains paramount and we are continuing to work closely with Wiltshire Police, scientists, health experts from Public Health England and other partners."
Around 100 detectives from the Counter Terrorism Policing Network continue to work on this investigation, alongside colleagues from Wiltshire Police.
Officers from the investigation team have spoken to Charlie and will be speaking to him further to establish how he and Dawn came to be contaminated. This contact is being done in close consultation with the hospital and the doctors.
Anyone with information that may assist the investigation is urged to contact counter terrorism police on 0800 789 321.
The risk to the public in Salisbury and Amesbury remains low. We have not seen any further cases of illness linked to this incident. As a precaution Public Health England continues to advise the public not to pick up any strange items such as syringes, needles, cosmetics or similar objects made of materials such as metal, plastic or glass.
The advice remains "if you didn't drop it, then don't pick it up".
We would like to thank the public of Amesbury and Salisbury for their tremendous support and understanding that they have shown to officers from the Counter Terrorism Policing Network.
A dedicated helpline – 0800 092 0410 – has been set up for anyone with health concerns in relation to this incident.