A U.K. woman has died after being exposed to the same type of nerve agent used against a former Russian spy and his daughter, British police said in a statement Sunday.
London's Metropolitan Police said detectives have launched a murder investigation following the death of Dawn Sturgess, 44, at a hospital Sunday evening local time.
"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," Assistant Commissioner Neil Basu, the head of the U.K. counter terrorism policing, said in the statement.
A man previously identified as Charlie Rowley, 45, who was also exposed to the nerve agent, remains critically ill in a hospital, police said in the statement.
"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," Basu said.
Police said that on Saturday, June 30, authorities took Sturgess to the hospital after they were called to a residence in Amesbury, England, and found her collapsed there. Later that same day, police returned to the same address and found Rowley there. He had also fallen ill and was taken to the hospital.
Samples from the two showed they had been exposed to a nerve agent after touching a contaminated item, police said.
Authorities have said the military-grade nerve agent, Novichok, is the same used against former double agent Sergei Skripal and his daughter Yulia in Salisbury in March. The British government blamed Russia for the attack. Moscow has repeatedly denied any involvement.
In Sunday's statement, police said there was no evidence Sturgess and Rowley visited any of the sites that were decontaminated following the attempt against the Skripals.
"We are not in a position to say whether the nerve agent was from the same batch that the Skripals were exposed to," the statement added.
"The possibility that the two investigations might be linked is clearly a key line of inquiry for police," police said in the statement. "However, it is important that the investigation is led by the evidence available and the facts alone."