Timeline: How the deadly novichok attack unfolded
The police have laid out details of Dawn Sturgess and Charlie Rowley's movements before they fell ill. Here is what we know.
Tuesday 10 July 2018 11:13, UK
Dawn Sturgess and Charlie Rowley are together at John Baker House - a supported housing scheme in Salisbury where Dawn was living.
It is about half a mile from the Zizzi restaurant where the Skripals dined before becoming ill.
They then leave and visit a number of shops in Salisbury before going to Queen Elizabeth Gardens.
They return to John Baker House.
They catch a bus to Amesbury at about 10pm - and police believe they spend the night at Muggleton Road, where Mr Rowley lives.
South West Ambulance Service is called to Muggleton Road where Dawn Sturgess is taken ill. Charlie Rowley is also present at the address.
Mr Rowley visits a Boots chemist on Stonehenge Walk in Amesbury and then returns to his home on Muggleton Road about half an hour later.
Mr Rowley visits the Amesbury Baptist Centre about a mile from his house.
Mr Rowley returns home.
At some point in the day before falling ill, Mr Rowley travels as a passenger in a red Ford Transit van.
The vehicle is taken to Porton Down for examination.
Three other men who were also in the van that day showed no signs of illness or exposure to novichok.
The South West Ambulance Service is called back to the address on Muggleton Road and Mr Rowley is also taken to hospital.
Wiltshire Police warn of the dangers of contaminated drugs after the couple fall ill.
Detectives believe they may have taken heroin or crack cocaine. Police say the pair are in a serious condition at Salisbury District Hospital.
Police declare a "major incident" after revealing that Ms Sturgess and Mr Rowley have been exposed to an "unknown substance". Several locations across Amesbury and Salisbury are cordoned off.
On the evening of 4 July, Scotland Yard reveals the couple have been exposed to novichok after tests at Porton Down.
Home Secretary Sajid Javid accuses the Russian state of using Britain as a "dumping ground for poison", and demands that the Kremlin provides an explanation for this incident as well as the Skripal case.
Forensic investigators in hazardous material suits and gas masks begin searching the building where Ms Sturgess lived.
A police officer attends hospital over concerns of a possible exposure to novichok but later tests negative for the nerve agent.
Ms Sturgess dies in hospital, with police launching a murder inquiry. Prime Minister Theresa May says she is "appalled and shocked" by her death, while Public Health England urges the public to avoid picking up "any strange items such as needles, syringes or unusual containers".