The people who shared the vehicle with Mr Rowley are being kept under observation by doctors but so far none of them have shown "any signs of having been exposed to the nerve agent or feeling unwell", Neil Basu, Britain's most senior counter-terrorism officer, said.
Her partner Charlie Rowley, 45, is still in a critical condition after the couple fell ill in Amesbury, Wiltshire, last Saturday.
Earlier reports about Sturgess suggested that she and Rowley handled a contaminated item and tests have confirmed the contamination spread through their hands.
Mr Basu also said 21 people have presented with "concerns" over possible exposure, they have been given "the all-clear".
A post-mortem examination of Sturgess, a native of nearby Durrington, will take place after her family is informed of her death.
Skripal and his daughter were both released from the hospital this spring.
This poses "a danger not only for the British, but for other Europeans", he said.
Police said they could not yet say whether the nerve agent in the Amesbury case was linked to the Salisbury attack - but it was their main line of inquiry.
Britain has blamed Russian Federation for the poisonings, but Moscow has strongly denied any involvement.
"I am appalled and shocked by the death of Dawn Sturgess, and my thoughts and condolences go to her family and loved ones".
"The circumstances in the Amesbury situation are troubling: recently, such cases emerge ahead of important events", Aleksandr Shulgin, Russia's envoy to the Organization for the Prohibition of Chemical Weapons, was quoted by the Izvestia newspaper as saying in an interview published July 9.
The Skripals fell ill after the poison was applied to the ex-spy's front door in the city of Salisbury. "It is more of a British issue and the question is to what extent Great Britain is interested in conducting a real investigation", he noted.
Britain, which blamed Russian Federation for the attack against the Skripals, so far has not directly pointed the finger at Russian Federation in the case involving Sturgess and Rowley, saying the investigation, led by the Counter Terrorism Policing Network, is ongoing.
Ms Sturgess's son Ewan, 19, fears his mother might not emerge from her coma.
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