Mr Rowley, 45, from Amesbury, remains in a critical condition in hospital.
Britain has blamed Moscow for the attack on the Skripals.
Russian Federation denies any involvement in the Skripals' case. Police are now hunting for that container, which they believe was likely linked to the attack on the Skripals four months earlier.
A post-mortem examination of Ms Sturgess, from Durrington, is due to take place and her family has been informed, police said.
"Just like before, we are deeply concerned that toxic substances continue to surface on British soil", Peskov said. Mr Rowley (inset), who had the highest concentrations of the nerve agent on his hands, is seen buying cans of super-strong lager and sharing a laugh with the cashier, who takes his money and packs up the alcohol for him.
"So as I said, it does remain our main line of inquiry but we are police officers and we have to work on evidence, so I would need a forensic link to make that absolutely 100% certain".
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Novichok, which the Soviets developed in the 1970s and 1980s as a next-generation nerve agent deadlier than others like VX or sarin, was the chemical authorities identified as the substance behind the poisoning of former double agent Sergei Skripal, his daugher Yulia, and a police officer in Salisbury in March.
Mr Basu said no one else in the Amesbury and Salisbury region, where the couple lived in south-western England, had shown any sign of Novichok poisoning.
Counter-terrorism chief Neil Basu said: 'Our focus and priority is to identify and locate any container that we believe may be the source of the contamination'. Police said there is no evidence that either Sturgess or Rowley visited any of the sites where the Skripals may have been poisoned.
Police are still trying to piece together how Ms Sturgess and Mr Rowley came into contact with Novichok.
Last week, the Chief Medical Officer for England said that the risk to the wider public remains low but that people in the local area should not pick up any odd items such as needles, syringes or unusual containers, given the source of the contamination has not yet been found. That afternoon, Rowley fell ill at the same address in Amesbury and was also hospitalised.
'But we must not lose sight of the fact that responsibility for the fact that a military-grade nerve agent was used in Salisbury and South Wiltshire, rests with Vladimir Putin's Kremlin alone'.