A neighbour claimed the couple were exposed to the agent at Queen Elizabeth Gardens in Salisbury - just a four-minute walk away from the bench outside The Maltings shopping centre where the Skripals were found poisoned earlier this year.
Per CNN, authorities now believe that Sturgess and Rowley came into contact with a contaminated item via their hands, but now lack the ability to determine whether the poison is from the same batch that the Skripals ingested.
He said: "I want to take the opportunity to say to everyone, but especially local people, that the risk to the public remains low". Five hours after her collapse, police said, an ambulance was called back to the same address for Rowley, who also fell ill and was taken to the hospital.
Met Police assistant commissioner Mr Basu said: 'Detectives from the UK's counter-terrorism policing network are unable to say at this moment whether or not the nerve agent found in this incident is linked to the attack on Sergei and Yulia Skripal, however this remains our main line of inquiry.
The attack on the Skripals worsened the already tense relations between Russia and the West, prompting the expulsion of Russian diplomats and embassy workers from several countries and retaliatory expulsions by Moscow.
The Russian government previously accused British intelligence officials of carrying out the Skripal poisoning as a way to stir up anti-Moscow sentiment.
The police have now opened a murder investigation into Sturgess' death.More news: Japan floods: Dozens killed in deluges and landslides
While the British authorities have not accused Russian Federation of involvement in the new incident, saying that their working assumption is that the British have been poisoned by the traces of nerve agents left over from the initial attack.
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"Our hypothesis is that they must have handled a container we are now seeking", he said.
A relative at Sturgess's family home in Durrington, near Amesbury, said the family was "devastated" but declined to comment further.
Public Health England, which oversees public health and epidemiological surveillance, said the risk to the general public "remains low", but advised against picking up odd items like needles, syringes, and unusual containers.
Detectives are working to identify the source of the contamination, police said, but a source has not yet been established.
"Wash your clothes in a washing machine and to keep your items double-bagged and securely fastened, if they are dry-cleaned only", he said.
It is not believed that the couple in the latest poisoning incident had visited the sites connected to the Skripals in Salisbury, he said.
The Skripal case, which Metropolitan Police detectives are investigating as attempted murder, sparked a diplomatic crisis between Russian Federation and the West, including the expulsion of hundreds of diplomats from both sides.
A Kremlin spokesman Monday expressed condolences over Sturgess' death.