British woman poisoned by Soviet nerve agent dies.

A British woman has died after being exposed to the Soviet-era nerve agent used in the poisoning of a Russian ex-spy and his daughter in March.

Dawn Sturgess, 44, died Sunday night in a Salisbury hospital while being treated for poisoning from Novichok, a military-grade chemical weapon, according to British authorities. Her boyfriend, Charlie Rowley, was also exposed and remains in a coma, in critical condition.

Sturgess’ death is being investigated as a murder, Prime Minister Theresa May announced in a tweet later on Sunday.

It’s not clear how Sturgess came in contact with the nerve agent or whether it came from the same batch that poisoned a former Russian spy in March. Friends told the British press that Rowley would often search dumpsters, and some investigators have hypothesized that Sturgess and Rowley accidentally touched items contaminated with the nerve agent thrown away by the assailants. Authorities said Sturgess absorbed the nerve agent through her hands.

Former Russian spy and double agent Sergei Skripal and his daughter, Yulia, fell into comas four months ago but were revived and released. British authorities accused Russia of being behind a deliberate attack, and the UK expelled 23 Russian diplomats as a result. Western allies, including the U.S., followed suit. Russia, which denied any involvement, retaliated by expelling dozens of British and American diplomats.

Around 100 detectives are working to identify the source of the Novichok, according to British authorities. Public health officials have said that the threat to the public remains low.

• Russia
• United Kingdom