They are also looking into where the couple came in contact with the poison, including searching the Queen Elizabeth gardens, a Salisbury homeless hostel where Sturgess, 44, lived and a red Ford Transit van 45-year-old Rowley traveled in hours before being rushed to the hospital.
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.
Russia, which is now hosting the soccer World Cup, has denied any involvement in the March incident and suggested the British security services had carried out the attack to stoke anti-Moscow hysteria.
Prime Minister Theresa May said she was "appalled and shocked" by Sturgess's death.
The investigation is being led by detectives from Britain's Counter Terrorism Policing Network and around 100 detectives are working round the clock alongside colleagues from Wiltshire police.
"This latest horrendous turn of events has only served to strengthen the resolve of our investigation team as we work to identify those responsible for this outrageous, reckless and barbaric act", counter-terrorism police chief Neil Basu said.
Dawn Sturgess, who has died as a result of Novichok poisoning, is pictured in Salisbury, Britain June 27, 2016, in this picture obtained from social media.
The couple were exposed to the substance just a few miles from where Sergie Skripal and his daughter encountered the toxic nerve agent, just four months ago. Although the United Kingdom has not officially blamed Russia for the latest poisoning, Russian officials have already denied any Kremlin involvement.
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Police say the nerve agent that sickened Rowley and Sturgess was the same type that nearly killed the Skripals, but scientists haven't been able to tell whether it was from the same batch.
The search is focused on their homes and a park in Salisbury.
Specialists at the nearby Defense Science and Technology Laboratory at Porton Down, a military research facility, identified the agent used against the Skripals, Sturgess and Rowley as Novichok.
The Metropolitan police have launched a murder investigation after Dawn Sturgess, 44, from Durrington died.
"Our current advice, based on the small number of casualties affected remains that the risk to the public is low", Paul Cosford, Director at Public Health England has said in a statement.
Police said there is no evidence that either Sturgess or Rowley visited any of the sites where the Skripals may have been poisoned.
The Kremlin said it would be "absurd" to suggest Russian Federation was involved in the death of Sturgess.
Basu said 21 other people who have been screened for Novichok exposure have been given the all-clear.