Police have launched a murder inquiry after a woman who was exposed to the nerve agent novichok in Wiltshire in the south-west of England died on Sunday evening.
Dawn Sturgess, 44, from Durrington, and a second person, Charlie Rowley, 45, fell critically ill last Saturday. Police investigating the incident have said they believe they had handled an item contaminated with the substance.
After a week receiving care in Salisbury Hospital, detectives announced shortly before 10pm on Sunday night that Ms Sturgess had died.
Assistant Commissioner Neil Basu, the head of UK Counter Terrorism policing said: “This is shocking and tragic news. Dawn leaves behind her family, including three children, and our thoughts and prayers are with them at this extremely difficult time.
“This terrible news has only served to strengthen our resolve to identify and bring to justice the person or persons responsible for what I can only describe as an outrageous, reckless and barbaric act.”
The latest developments come four months after the nerve agent attack on the former Russian double agent Sergei Skripal and his daughter Yulia in Salisbury.
The Metropolitan Police’s counter terror command said it was investigating whether Ms Sturgess and Mr Rowley were accidental victims of the same attack, which the UK has blamed on Russia.
The death of Ms Sturgess is likely to raise tensions between the UK and the Russian government which has repeatedly denied it was behind the attempted murder of the Skripals.
Prime Minister Theresa May said: ‘I am appalled and shocked by the death of Dawn Sturgess, and my thoughts and condolences go to her family and loved ones. Police and security officials are working urgently to establish the facts of this incident, which is now being investigated as a murder.
‘The Government is committed to providing full support to the local community as it deals with this tragedy.’
Police said Mr Rowley remained critically ill in hospital.
Mr Basu added: “Detectives will continue with their painstaking and meticulous work to gather all the available evidence so that we can understand how two citizens came to be exposed with such a deadly substance that tragically cost Dawn her life.”